US endangered-species recovery surges to record high

The Santa Cruz Island Fox is one of three subspecies of fox removed from the Endangered Species Act list this month.

More species protected by the US Endangered Species Act (ESA) have recovered during President Barack Obama’s administration than under all other presidents combined, the US Department of Interior announced on 11 August. And 2016 marks a record high for species recovery, with six so far officially ‘delisted’ from ESA’s roster.

The ESA, passed in 1973 to assist the recovery and protection of imperilled species and ecosystems, is widely seen as a landmark piece of environmental legislation. During Obama’s presidency, 19 species have now recovered and been delisted; this compares to seven such removals under George W. Bush, six during Bill Clinton’s administration and five under Ronald Reagan. Source: US Dept. Interior/US Fish & Wildlife Service.

That may simply be a result of the 43-year-old ESA legislation finally starting to pay dividends, says Noah Greenwald, director of endangered species at the Center for Biological Diversity, a non-profit conservation group headquartered in Tucson, Arizona. “It also reflects the fact that the Obama administration has been putting more resources into processing delistings for recovered species, in an effort to counter attacks from Republicans in Congress who say the law has a poor success rate,” he adds.

The latest delistings are of three subspecies of fox native to California’s Channel Islands (Urocyon littoralis ssp.). The Department of Interior says that the foxes, listed in 2004, represent the “fastest successful recovery” of any ESA mammal, crediting efforts including a captive-breeding programme and a vaccination campaign against a canine virus.

But the ESA process does not move as quickly as it should when it comes to listing species for protection in the first place, according to research by Greenwald and his colleagues. In a report published last month, they calculate that it takes a species on average 12 years to be listed after first consideration — much more than the two years that the law says it should.

Nature doi:10.1038/nature.2016.20448 Read a previous Trend Watch: ‘US grants for zebrafish studies on the rise’  Nature Original web page at Nature


Sexual rivalry may drive frog reproductive behaviors

It may be hard to imagine competing over who gets to kiss a frog, but when it comes to mating, a new study concludes that some frogs have moved out of the pond onto land to make it easier for the male in the pair to give sexual rivals the slip.

Biologists have long thought that some frog species evolved to mate on land — sometimes in unusual places — instead of in open water to better guard eggs and tadpoles from easily being eaten by fish and other predators. But the new research by a team of U.S. and Brazilian frog biologists suggests that mating on land in many species might in part be a strategy that male frogs use to ensure that their own DNA gets passed on, instead of the DNA of their rivals. Sexual selection may trump natural selection in the evolution of these reproductive behaviors, according to the new study, to be published online ahead of print on July 26 in The American Naturalist.

Frogs have a “dizzying array” of reproductive strategies, according to Rayna Camille Bell, a UC Berkeley postdoctoral fellow who contributed to data collection, analyzed and interpreted much of the data, and helped co-author the study, which was led by her doctoral thesis advisor, Kelly Zamudio, a professor at Cornell University.

Mating in frogs typically involves the male wrapping his arms around the female, the female depositing eggs and the male fertilizing the eggs, which will hatch into tadpoles and ultimately develop into froglets. The earliest frogs completed all of these steps in water, but among different frog species there are various strategies for accomplishing these reproductive tasks before a new generation hops or swims off on its own. Frog species vary in where they mate, where they lay eggs, where tadpoles develop and whether and how eggs and tadpoles are tended to by parent frogs. Some species even skip the egg stage, giving birth to live tadpoles or even froglets.

“Biologists noticed an apparent linear progression toward more terrestrial reproduction throughout frog evolution and proposed that frogs avoid putting their eggs and tadpoles in streams or ponds because they would be more vulnerable to aquatic predators,” Bell said. The apparent trend toward increasingly terrestrial reproduction is most evident in tropical frogs, perhaps because more humid environments more easily permit reproduction on land without eggs or tadpoles drying up.

But eggs and tadpoles are still susceptible to predators on land, and biologists haven’t reached a consensus on why so many tropical frog species have terrestrial reproductive modes. If natural selection to minimize aquatic predation on developing eggs and tadpoles was the main driver for evolving terrestrial reproduction, Bell and her collaborators reasoned, there should be equally diverse strategies for placing both eggs and tadpoles out of harm’s way.

But in reviewing datasets built upon the field work of other biologists and their own data on hundreds of species in two different families of tropical frogs, the Hylidae and Leptodactylidae, the researchers found that this was not generally the case.

They found that most of the diversity in reproductive strategies involves the egg stage. Even when eggs are deposited on land, tadpoles often quickly end up in dangerous waters, falling off a leaf into a stream, for instance. This pattern indicates that selection is acting independently on eggs versus tadpoles, Bell said, suggesting that there might be other evolutionary advantages of depositing eggs on land.

“Besides avoiding aquatic predators, the benefit of depositing your eggs on land away from the main body of water — if you are a male frog — is that you get the female away from the breeding frenzy where there are hundreds of males all competing for access to females,” Bell said. “On land, it’s easier to make sure that no other male is moving in on your female and fertilizing her eggs.”

Bell and co-authors found that when mating occurs away from the main body of water, the mating site is often more private and hidden from competing males. Some frog species mate in the water-containing folds of bromeliad leaves, for example, and males in other species even build volcano-shaped mud nests that they may guard while mating.

The researchers hypothesized that if sexual selection is playing a role in the evolution of these mating behaviors, then in species where competition for fertilizing eggs is fierce males should have larger sperm-producing testes, similar to what has been observed in other animals where male competition for mates is intense. Conversely, males in species with private breeding sites should have smaller testes.

Indeed, Bell and colleagues determined that the mass of male testes, which is a proxy for sperm competition, is smaller and less variable in frogs that hide while breeding, indicating they are less vulnerable to other males horning in.

What is special about the tropics?

Most studies of frog mating systems have been in temperate regions. Like this study, new natural history data on mating systems and reproductive modes in both temperate and tropical frog species are likely to challenge preconceived notions of how and why these complex reproductive behaviors evolved, Bell said.

“The tropics have the greatest frog species diversity, as well as the most diversity and complexity in frog reproductive modes,” Bell said, “But we know the least about the biology, behavior and diversity of these tropical species, even though many are threatened, and some are only now being discovered for the first time. Hopefully our study will draw attention to how much we still have to learn about sexual selection and mating system dynamics in frogs.”  Science Daily Original web page at Science Daily


A study led by researchers at The University of Nottingham has discovered that the fertility of dogs may have suffered a sharp decline over the past three decades

The research, published in the academic journal Scientific Reports, found that sperm quality in a population of stud dogs studied over a 26-year period had fallen significantly.

The work has highlighted a potential link to environmental contaminants, after they were able to demonstrate that chemicals found in the sperm and testes of adult dogs — and in some commercially available pet foods — had a detrimental effect on sperm function at the concentrations detected.

As ‘man’s best friend’ and closest companion animal, the researchers believe that the latest results may offer a new piece of the puzzle over the reported significant decline in human semen quality — a controversial subject which scientists continue to debate.

Dr Richard Lea, Reader in Reproductive Biology in the University’s School of Veterinary Medicine and Science, who led the research said: “This is the first time that such a decline in male fertility has been reported in the dog and we believe this is due to environmental contaminants, some of which we have detected in dog food and in the sperm and testes of the animals themselves.

“While further research is needed to conclusively demonstrate a link, the dog may indeed be a sentinel for humans — it shares the same environment, exhibits the same range of diseases, many with the same frequency and responds in a similar way to therapies.”

The study centred on samples taken from stud dogs at an assistance dogs breeding centre over the course of 26 years. Professor Gary England, Foundation Dean of the School of Veterinary Medicine and Science and Professor of Comparative Veterinary Reproduction, who oversaw the collection of semen said: “The strength of the study is that all samples were processed and analysed by the same laboratory using the same protocols during that time and consequently the data generated is robust.”

The work centred on five specific breeds of dogs — Labrador retriever, golden retriever, curly coat retriever, border collie and German shepherd — with between 42 and 97 dogs studied every year.

Semen was collected from the dogs and analysed to assess the percentage of sperm that showed a normal forward progressive pattern of motility and that appeared normal under a microscope (morphology).

Over the 26 years of the study, they found a striking decrease in the percentage of normal motile sperm. Between 1988 and 1998, sperm motility declined by 2.5 per cent per year and following a short period when stud dogs of compromised fertility were retired from the study, sperm motility from 2002 to 2014 continued to decline at a rate of 1.2% per year.

In addition, the team discovered that the male pups generated from the stud dogs with declining semen quality, had an increased incidence of cryptorchidism, a condition in which the testes of pups fail to correctly descend into the scrotum.

Sperm collected from the same breeding population of dogs, and testes recovered from dogs undergoing routine castration, were found to contain environmental contaminants at concentrations able to disrupt sperm motility and viability when tested.

The same chemicals that disrupted sperm quality, were also discovered in a range of commercially available dog foods — including brands specifically marketed for puppies.

Dr Lea added: “We looked at other factors which may also play a part, for example, some genetic conditions do have an impact on fertility. However, we discounted that because 26 years is simply too rapid a decline to be associated with a genetic problem.”

Over the past 70 years, studies have suggested a significant decline in human semen quality and a cluster of issues called ‘testicular dysgenesis syndrome’ that impact on male fertility which also include increased incidence of testicular cancer, the birth defect hypospadias and undescended testes.

However, declining human semen quality remains a controversial issue — many have criticised the variability of the data of the studies on the basis of changes in laboratory methods, training of laboratory personnel and improved quality control over the years.

Dr Lea added: “The Nottingham study presents a unique set of reliable data from a controlled population which is free from these factors. This raises the tantalising prospect that the decline in canine semen quality has an environmental cause and begs the question whether a similar effect could also be observed in human male fertility.” Science Daily  Original web page at Science Daily


Our ancestors evolved faster after dinosaur extinction

Our ancestors evolved three times faster in the 10 million years after the extinction of the dinosaurs than in the previous 80 million years, according to UCL researchers.

The team found the speed of evolution of placental mammals — a group that today includes nearly 5000 species including humans — was constant before the extinction event but exploded after, resulting in the varied groups of mammals we see today.

Lead researcher, Dr Thomas Halliday (UCL Genetics, Evolution & Environment), said: “Our ancestors — the early placental mammals – benefitted from the extinction of non-avian dinosaurs and dwindling numbers of competing groups of mammals. Once the pressure was off, placental mammals suddenly evolved rapidly into new forms.

“In particular, we found a group called Laurasiatheria quickly increased their body size and ecological diversity, setting them on a path that would result in a modern group containing mammals as diverse as bats, cats, rhinos, whales, cows, pangolins, shrews and hedgehogs.”

The team found that the last common ancestor for all placental mammals lived in the late Cretaceous period, about three million years before the non-avian dinosaurs became extinct 66 million years ago. This date is 20 million years younger than suggestions from previous studies which used molecular data from living mammals and assumed a near-constant rate of evolution.

In this study, funded by the Natural Environment Research Council and published today in Proceedings B of the Royal Society, the researchers analysed fossils from the Cretaceous to the present day, and used the dates of their occurrence in the fossil record to estimate the timing of divergences based on an updated tree of life. The new tree was released by the same team in 2015 and has the largest representation of Paleocene mammals to date.

The scientists measured all the small changes in the bones and teeth of 904 placental fossils and mapped the anatomical differences between species on the tree of life. From measuring the number of character changes over time for each branch, they found the average rate of evolution for early placental mammals both before and after the dinosaur extinction event. They compared the average rate of evolution over the geological stages before the extinction and the geological stages after to see what impact it had.

Senior author, Professor Anjali Goswami (UCL Genetics, Evolution & Environment and UCL Earth Sciences), said: “Our findings refute those of other studies which overlooked the fossils of placental mammals present around the last mass extinction. Using rigorous methods, we’ve successfully tracked the evolution of early placental mammals and reconstructed how it changed over time. While the rate differed between species, we see a clear and massive spike in the rates of evolution straight after the dinosaurs become extinct, suggesting our ancestors greatly benefitted from the demise of the dinosaurs. The huge impact of the dinosaur extinction on the evolution of our ancestors really shows how important this event was in shaping the modern world.”

Professor Paul Upchurch (UCL Earth Sciences), co-author of the study, added: “Our large and refined data set allows us to build a clearer picture of evolutionary history. We plan on using it to study other large-scale evolutionary patterns such as how early placental mammals dispersed across the continents via land bridges that no longer exist today.”  Science Daily Original web page at Science Daily


World’s first successful artificial insemination of southern rockhopper penguin

DNA tests have confirmed that one of the three southern rockhopper penguin chicks born at Osaka Aquarium Kaiyukan between June 4 and 6 was conceived through artificial insemination. This is the result of a project led by Kaiyukan with the collaboration of Associate Professor KUSUNOKI Hiroshi (Kobe University Graduate School of Agricultural Science). It is the world’s first successful case of a southern rockhopper penguin being conceived through artificial insemination.

Southern rockhopper penguins are a species of birds approximately 50cm in height which inhabit southern islands near Antarctica such as the Falkland Islands. They are on the red list of the International Union for Conservation of Nature as a threatened species.

Kaiyukan and Associate Professor Kusunoki began their joint research in 2011, aiming to elucidate the breeding habits of southern rockhopper penguins and develop the technology for their artificial insemination. In spring 2015 the group obtained a fertilized egg, but the chick did not hatch, and DNA tests determined that the unborn chick was the result of natural reproduction.

This time multiple penguins were selected for breeding, and the group enlisted the cooperation of Tokyo Sea Life Park, where scientists had previously succeeded in breeding species through natural reproduction. At the end of April they obtained a healthy sperm sample from a male penguin at Tokyo Sea Life Park and transported it to Kaiyukan without loss of quality. At Kaiyukan they used blood tests to estimate the laying days of three female penguins and determine the best timing for artificial insemination.

Between April 28 and May 4 the three female penguins laid five eggs between them. These were incubated by the penguin couples for approximately one month, and three chicks hatched between June 4 and 6. Results of DNA tests carried out on blood samples taken from inside the eggshells revealed that one of these chicks was conceived through artificial insemination. Science Daily  Original web page at Science Daily


Tropical birds develop ‘superfast’ wing muscles for mating, not flying

Studies in a group of tropical birds have revealed one of the fastest limb muscles on record for any animal with a backbone. The muscle, which can move the wing at more than twice the speeds required for flying, has evolved in association with extravagant courtship displays that involve rapid limb movements, according to a paper to be published in the journal eLife.

The ‘superfast’ wing movements of male red-capped and golden-crowned manakins are undetectable to the human eye, and are about six to eight times faster than the 8-hertz (Hz) speed at which a sprinter, such as Olympian athlete Usain Bolt, moves their legs through the air in a 100-metre run.

“The discovery of the superfast wing muscle in these birds paves the way for further studies into what has to change, or what can change, in a muscle to make it drive faster movements,” says first author Matthew Fuxjager, from Wake Forest University.

“This could be important for developing therapies for motor disorders, particularly those characterized by decreases in muscle performance that result from diseases such as cancer and HIV.”

Many different species perform rapid limb movements as part of their courtship displays, from certain birds running across lake surfaces, to the unusual boxing displays of hares in March.

However, because muscle performance is limited by trade-offs between speed and force, it is unclear how animals develop the ability to generate both the swift movements involved in showy physical displays and the force needed to drive these movements.

To address this question, Fuxjager and his team compared the twitch speeds of forelimb muscles from wild-caught golden-collared and red-capped manakins to those of three other related species: the blue-crowned manakin, the dusky antbird, and the house wren.

“Of the species studied, the golden-collared and red-capped manakins produce exceptionally rapid wing movements as part of their acrobatic courtship displays,” Fuxjager explains.

“For example, the golden-collared manakins perform ‘roll-snaps’, whereby they hit their wings together above the back at around 60 Hz to produce a loud mechanical sound. Likewise, red-capped manakins produce a similar wing sonation called a ‘clap’, in which the wings are extended slightly above the body and immediately retracted back to the sides in quick succession, at around 45 Hz.”

To explain these birds’ abilities to move their limbs rapidly during courtship performances, the researchers investigated the differences in muscle contraction speeds by comparing the half-relaxation frequency among the five different species. This represents the frequency at which each wing muscle is stimulated to contract, while still being able to relax to half their length following stimulation, thereby showing an accurate measure of how quickly they can contract.

For two of the three wing muscles, the half-relaxation frequencies averaged around 50 Hz and were indistinguishable among species. By contrast, the frequency measures in the main muscle that retracts the humerus were significantly higher in both the golden-collared and red-capped manakins. Estimates of their half-relaxation frequencies in this muscle were exceptionally high, and the frequencies between the two birds were indistinguishable.

These results show that only the golden-collared and red-capped manakins have evolved superfast contractile movements in their main humeral retractor muscle. The other two muscles that generate the majority of aerodynamic force for flight are no different from those of other birds, suggesting that they have been preserved to produce the strength needed for flying.

The team also found that the humeral retractor muscle in golden-collared and red-capped manakins is more than capable of driving the natural wing oscillations that make up their impressive displays.

Taken together, the results suggest that muscle-specific adaptations in contractile speed allow certain birds to avoid the trade-off between muscular speed and force, thereby using their forelimbs for both rapid gestural displays and powered locomotion.

“Further studies could now explore how this one muscle can create such superfast wing movements and whether male hormones, such as testosterone, play a role in regulating the muscle’s speed,” Fuxjager adds.

“If we discover whether steroids regulate the muscle’s ability to contract at superfast speed, we would be uncovering how hormones can ‘turn on’ or ‘turn off’ its extraordinary ability. This would open the door to understanding how rapid limb movements are regulated in accordance with the animals’ reproductive environment.”  Science Daily  Original web page at Science Daily


Multiple paternity may offer fewer advantages than previously thought

Females can enhance the survival chances of their offspring by mating with multiple males. When it comes to immunological benefits, however, female promiscuity may not provide the young the advantages long suspected, as a research team from Vetmeduni Vienna confirmed. The researchers also provided the first evidence that females are much more susceptible to Salmonella infection than males. The study was published in the Journal of Evolutionary Biology.

Promiscuity is common among females in the animal kingdom. Mating with multiple males can increase genetic diversity and enhance the survival of the offspring. When given a choice, female house mice mate with multiple males. “The females select their partner on the basis of their scent markings. These chemical signals provide a surprising amount of information about possible partners, including their health and disease resistance,” explains Kerstin Thonhauser of the Konrad Lorenz Institute for Ethology at Vetmeduni Vienna.

The team of researchers led by Dustin Penn explored the previously unanswered question whether polyandry in house mice also offered an advantage in terms of immune resistance. The researchers challenged animals from single- and multiple-sired litters with two different strains of Salmonella: a primary infection, which was harmless, and effectively a vaccine, and then a secondary infection. Prior to the study, there had been little sex-specific data concerning the immune response to Salmonella infection, so the team also considered this question in their study.

Polyandry offered mice no advantages against Salmonella. In general, there was an enormous variation in the bacterial clearance among the mice, and especially among different families, but no difference was found between single- and multiple sired offspring. These results do not support the hypothesis that the increased genetic diversity of multiple-sired litters enhances immune resistance.

Male mice were surprisingly resistant. Among mice, males are usually more susceptible to infectious diseases, yet in the case of Salmonella, however, this proved not to be the case. The immune system of male mice handled this challenge better than the females, as was confirmed by the lower bacterial load among males. No other study to date has demonstrated such a sex-dependent response for Salmonella. Unfortunately, most studies on mice have focused on males, as a way to control for variation in female reproductive cycling, and so we understand little about sex differences. Such sex difference should be considered in future immunological research, says Thonhauser.

Time to reconsider hypotheses on multiple paternity. Nonetheless, Thonhauser and colleagues stress that female promiscuity could still provide immunological benefits for offspring by reducing disease transmission within litters. “There are additional factors to consider. It is possible that a multiple paternity protects litters against challenges from multiple pathogens. Our study was a first step towards testing these more complicated scenarios regarding the advantages of multiple paternity.” Science Daily  Original web page at Science Daily



* Inbreeding impacts on mothering ability, red deer study shows

Inbred animals have fewer surviving offspring compared with others, a study of red deer in the wild has found. The insight could aid the conservation and management of endangered populations of animals in which inbreeding carries a high risk of extinction.

The findings from a long-term study on a Scottish island shows that hinds whose parents were first cousins raise far fewer offspring – about one-quarter as many – to adulthood over their lifetimes compared with others.

This is because inbred hinds are less likely to survive to breeding age, to have a calf in any given year and to rear any calves they do have to independence.

Similarly, male red deer born to first cousins sire only one-twentieth the number of offspring of average adult males.

Inbreeding is known to have adverse effects across many species, but examples of its impact on adult wild animals are rare.

Researchers used a DNA screening tool to gain a highly detailed measure of inbreeding for each individual deer living at the study site on the Isle of Rum in the Inner Hebrides.

They used this alongside long-term data on individuals from the 40-year study to determine the extent of inbreeding on the ability of each animal to reproduce and successfully raise offspring.

Red deer on Rum are occasionally inbred because some males return to the part of the island where they were born for the annual rut, where they encounter their sisters, aunts and cousins.

The herd is not endangered nor at risk from the inbreeding effects highlighted in the study, but the results are important for endangered populations, in which a lack of unrelated mating partners often increases inbreeding.

The study, published in Proceedings of the National Academy of Sciences, and carried out by scientists at the Universities of Edinburgh and Cambridge and the Australian National University, was supported by the European Research Council and the Natural Environment Research Council.

The Isle of Rum National Nature Reserve is owned and managed by Scottish Natural Heritage.

Professor Josephine Pemberton of the University of Edinburgh’s School of Biological Sciences, who led the study, said: “Combining sophisticated genetic analysis techniques with long-term data on individual deer life histories has revealed surprising results about how damaging inbreeding is in adult life. Inbred mothers give birth to calves whose chances of survival are almost as bad as if the calves themselves were inbred.”

Chris Donald, SNH’s South Highland Operations Manager, said: “This cutting-edge research from our national nature reserve on Rum has produced some exceptional insights into the health and survival of red deer. This work will clearly have considerable implications on how we conserve and manage endangered deer populations where the risks of inbreeding are high.”  Science  Daily  Original web page at Science Daily


Intense competition for reproduction results in violent mass evictions

Intense levels of reproductive competition trigger violent evictions of male and female banded mongooses from their family groups, University of Exeter researchers have found. Dominant animals in this species are unable to stop subordinates breeding, leaving them with no resort except to throw them, kicking and screaming, out of the group.

Scientists observed a population of wild banded mongooses in Queen Elizabeth National Park in south west Uganda in a 16 year study. They found that evictions were extremely aggressive events resulting in the forcible expulsion of a group of females, sometimes with a group of males alongside them.

These mass eviction events were most likely to occur when the level of competition over who reproduces was at its greatest. Female banded mongooses were evicted when there were lots of breeding females in the group, and males were more likely to be evicted alongside females when there were lots of males competing to breed.

Banded mongooses live in cooperatively breeding family groups, meaning that all group members help to raise pups even if they don’t breed themselves. All adult females breed together, giving birth to a communal litter on exactly the same day. Usually individuals live together peacefully but occasionally the group erupts into violence, which results in some individuals being aggressively attacked and driven away from the group.

The study, published in the journal Proceedings of the Royal Society B, shows that reproductive competition destabilises cooperative groups and that eviction can be a major source of gene flow in social animals.

Faye Thompson, a PhD researcher at the University of Exeter’s Centre for Ecology and Conservation and the lead author of the study, said: “Banded mongooses, like many social animals, often show extreme levels of cooperation but occasionally these harmonious relations break down. Dominant females, and sometimes males too, aggressively evict members of their own family to reduce their level of reproductive competition.

“Banded mongooses rarely disperse of their own accord, and so eviction is one of the only ways that individuals form new groups. These eviction events result in the mass movement of genes through the population.”

Professor Michael Cant from the University of Exeter’s Penryn Campus, Cornwall, who leads the Banded Mongoose Research Project, said: “We’ve been studying these animals for 20 years, but it’s only now that we are beginning to understand the long-term dynamics of the system. This work shows that within-group conflicts can have effects not only on the individuals involved, but also on the genetic structure of the wider population.”  Science Daily  Original web page at Science Daily


Stem cell technique makes sperm in a dish

Scientists in China have finally succeeded in creating functioning sperm from mice in the laboratory. To accomplish this feat, the researchers coaxed mouse embryonic stem cells to turn into functional sperm-like cells, which were then injected into egg cells to produce fertile mouse offspring. The work, reported February 25 in Cell Stem Cell, provides a platform for generating sperm cells that could one day be used to treat male infertility in humans.

“Reproducing germ cell development in vitro has remained a central goal in both reproductive biology and reproductive medicine,” says co-senior study author Jiahao Sha of Nanjing Medical University. “We established a robust, stepwise approach that recapitulates the formation of functional sperm-like cells in a dish. Our method fully complies with the gold standards recently proposed by a consensus panel of reproductive biologists, so we think that it holds tremendous promise for treating male infertility.”

Infertility affects up to 15% of couples, and about one-third of cases can be traced to the man. One major cause of male infertility is the failure of precursor germ cells in the testes to undergo a type of cell division called meiosis to form functional sperm cells. Several studies have reported the successful generation of germ cells from stem cells, but they did not fully evaluate the functionality of the germ cells or provide proof for all key hallmarks of meiosis.

Recently, a panel of reproductive biologists proposed gold standard criteria to prove that the major events of meiosis have taken place in engineered germ cells. For example, researchers must show evidence of the correct nuclear DNA content at specific meiotic stages, normal chromosome number and organization, and the capacity of germ cells to produce viable offspring. Until now, the recapitulation of all of the essential steps of meiosis has remained a major obstacle to the production of functional sperm and egg cells in a dish.

To overcome this hurdle, Sha teamed up with co-senior study authors Qi Zhou and Xiao-Yang Zhao of the Institute of Zoology at the Chinese Academy of Sciences to develop a stem cell-based method that fully recapitulates meiosis and produces functional sperm-like cells. The first step was to expose mouse embryonic stem cells (ESCs) to a chemical cocktail, which coaxed the ESCs to turn into primordial germ cells. Next, the researchers mimicked the natural tissue environment of these precursor germ cells by exposing them to testicular cells as well as sex hormones such as testosterone.

Under these biologically relevant conditions, the ESC-derived primordial germ cells underwent complete meiosis, resulting in sperm-like cells with correct nuclear DNA and chromosomal content. To provide final gold-standard proof of meiosis, the researchers injected these sperm-like cells into mouse egg cells and transferred the embryos into female mice. Remarkably, these embryos developed normally and gave rise to healthy, fertile offspring, which gave birth to the next generation.

In future studies, the researchers plan to use their platform to examine the molecular mechanisms controlling meiosis. They will also test their approach in other animals such as primates in anticipation of human studies. However, before this technique is translated to the clinic, possible risks must be ruled out and ethical concerns regarding the use of embryonic cells should be considered.

“If proven to be safe and effective in humans, our platform could potentially generate fully functional sperm for artificial insemination or in vitro fertilization techniques,” Sha says. “Because currently available treatments do not work for many couples, we hope that our approach could substantially improve success rates for male infertility.”  Science Daily  Original web page at Science Daily


Male mice without any Y chromosome genes can father offspring after assisted reproduction

The Y chromosome is a symbol of maleness, present only in males and encoding genes important for male reproduction. But a new study has shown that live mouse progeny can be generated with assisted reproduction using germ cells from males which do not have any Y chromosome genes. This discovery adds a new light to discussions on Y chromosome gene function and evolution. It supports the hypothesis that Y chromosome genes can be replaced by that encoded on other chromosomes.

Two years ago, the University of Hawaii (UH) team led by Monika A. Ward, Professor at the Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawai’i, demonstrated that only two genes of the Y chromosome, the testis determinant factor Sry and the spermatogonial proliferation factor Eif2s3y, were needed for male mice to sire offspring with assisted fertilization. Now, the same team, with a collaborating researcher from France, Michael Mitchell (INSERM, Marseille), took a step further and produced males completely devoid of the entire Y chromosome.

In this new study scheduled for online publication in the journal Science on Jan. 29, 2016, Ward and her UH colleagues describe how they generated the “No Y” males, and define the ability of these males to produce gametes and sire offspring.

The UH researchers first replaced the Y chromosome gene Sry with its homologue and direct target encoded on chromosome 11, Sox9. In normal situation, Sry activates Sox9, and this initiates a cascade of molecular events that ultimately allow an XY fetus to develop into a male. The researchers used transgenic technology to activate Sox9 in the absence of Sry.

Next, they replaced the second essential Y chromosome gene, Eif2s3y, with its X chromosome encoded homologue, Eif2s3x. Eif2s3y and Eif2s3x belong to the same gene family and are very similar in sequence. The researchers speculated that these two genes may play similar roles, and it is a global dosage of both that matters. They transgenically overexpressed Eif2s3x, increasing dose of the X gene beyond that provided normally by X and Y. Under these conditions, Eif2s3x took over the function of Eif2s3y in initiating spermatogenesis.

Finally, Ward’s team replaced Sry and Eif2s3y simultaneously, and created XOSox9,Eif2s3x males that had no Y chromosome DNA. Mice lacking all Y chromosome genes developed testes populated with male germ cells. Round spermatids were harvested and a technique called round spermatid injection (ROSI) was used to successfully fertilize oocytes. When the developed embryos where transferred to female mouse surrogate mothers, live offspring were born.

The offspring derived from the “No Y” males were healthy and lived for normal life span. The daughters and grandsons of the “No Y” males were fertile and capable of reproducing on its own without further technological intervention. Ward’s team produced three consecutive generations of “No Y” males using ROSI showing that males lacking Y chromosome genes can be repeatedly propagated with technical assistance.

“Most of the mouse Y chromosome genes are necessary for development of mature sperm and normal fertilization, both in mice and in humans,” Ward said. “However, when it comes to assisted reproduction, we have now shown that in the mouse the Y chromosome contribution is not necessary.”

The study provides new important insights into Y chromosome gene function and evolution. It supports the existence of functional redundancy between the Y chromosome genes and their homologues encoded on other chromosomes. “This is good news,” Ward said, “because it suggests that there are back-up strategies within genomes, which are normally silent but are capable of taking over under certain circumstances. We revealed two of these strategies by genome manipulation. Whether such alternative pathways would ever be activated without human help, for example in response to environmental changes, is unknown. But it is certainly possible and has already happened for two rodent species which lost their Y chromosomes. ”

The development of assisted reproduction technologies (ART) allows bypassing various steps of normal fertilization by using immotile, non-viable, or immature gametes. The newest study as well as Ward’s preceding report (Science 2014 Jan 3; 343 (6166: 69-72) support that in the mouse ROSI is a successful and efficient form of ART. In humans, ROSI is considered experimental due to concerns regarding the safety of injecting immature germ cells and other technical difficulties. The researchers hope that the success in mouse studies may spark the re-evaluation of human ROSI for its suitability to become an option for overcoming male infertility in the future.  Science Daily  Original web page at Science Daily


Sunshine vitamin linked to improved fertility in wild animals

High levels of vitamin D are linked to improved fertility and reproductive success, a study of wild sheep has found. The study, carried out on a remote Hebridean island, adds to growing evidence that vitamin D — known as the sunshine vitamin — is associated with reproductive health.

Experts hope that further studies will help to determine the relevance of the results for other mammals, including people.

Researchers led by the University of Edinburgh measured concentrations of a marker linked to vitamin D in the blood of an unmanaged population of Soay sheep, on St Kilda. Scientists found that sheep with higher levels of vitamin D in their blood at the end of the summer went on to have more lambs in the following spring.

The study offers the first evidence that an animal’s vitamin D status is associated with an evolutionary advantage. Vitamin D is produced in the skin of sheep and other animals, including people, after exposure to sunlight. It can also be found in some foods, including certain types of plants. It is essential for healthy bones and teeth and has been linked to other health benefits.

Many studies in the lab have linked vitamin D to reproductive health in animals and humans. This is the first evidence of the link in wild animals. Scientists carried out the research as part of a long-term study on the evolution of Soay sheep. The animals have lived wild for thousands of years on the islands of St Kilda, a world Heritage site owned and managed by the National Trust for Scotland. The research is published in the journal Scientific Reports. It was funded by the Wellcome Trust and the Natural Environment Research Council.

Dr Richard Mellanby, Head of Small Animal Medicine at the University’s Royal (Dick) School of Veterinary Studies, who led the research, said: “Our study is the first to link vitamin D status and reproductive success in a wild animal population.

“Examining the non-skeletal health benefits of vitamin D in humans is challenging because people are exposed to different amounts of sunlight each day. Studying the relationship between skin and dietary sources of vitamin D — and long term health outcomes — is more straightforward in sheep living on a small island.”  Science Daily  Original web page at Science Daily


Sexuality, not extra chromosomes, benefits animal, biologists find

Most animals, including humans, have two copies of their genome — the full set of instructions needed to make every cell, tissue, and organ in the body.

But some animals carry more than two complete sets of the genome, referred to as polyploidy. Biologists have long wondered whether these extra chromosomes help or hinder those species.

In a study involving multiple generations of a freshwater snail in New Zealand, researchers at the University of Iowa found that polyploidy appears to be neither an asset nor a drawback for females bearing offspring without the help of a male. Instead, it’s the snails’ sexuality that creates an advantage: Asexual females, the study found, grew twice as fast during the late juvenile phase and reached reproductive maturity 30 percent faster than female snails that mated with males.

That in itself raises fundamental biological questions: If asexual females grow faster and bear children much more quickly than sexual females, what’s the purpose of sex, and why is it the dominant method of reproduction in the animal world?

“When we did the study, we thought polyploidy would be bad for asexuals, but we didn’t find any evidence of that,” says Maurine Neiman, associate professor of biology at the UI and corresponding author on the paper, published in the journal Ecology and Evolution. “This is making the role of sex even harder to explain.”

The mud snails, Potamopyrgus antipodarum, live in lakes and streams all over New Zealand. They were also discovered in Idaho in 1987 and have since spread to the Great Lakes and farther east to Chesapeake Bay, according to the U.S. Department of Agriculture, which classifies the animals as an invasive species.

Sexual and asexual females are known to live in the same lakes in New Zealand, although they also exist separately in other lakes. Males will mate with either, but their genes are not passed on in encounters with asexual females. Those factors, and the snails’ abundance, made them a good species in which to test the effects of polyploidy.

The UI team compared sexually reproductive female snails with only two copies of their genome to asexual females carrying three and four copies. Together, they produced enough generations to occupy 1,500 cups — one cup per snail.

“When we began, we thought the project would take six to nine months,” says Katelyn Larkin, who earned her bachelor’s and master’s degrees in biology at the UI and has worked in Neiman’s lab since she was a sophomore. “Instead, it took more than three years. We learned that these snails grow at a snail’s pace.”

The asexual females, regardless of the number of genomic copies they possessed, grew faster and reached reproductive maturity quicker than the sexual females, the researchers discovered. In human terms, it’d be as if the asexual females could produce children at 13 years of age, whereas the sexual females wouldn’t reach reproductive age until age 18. Couple that with the fact that asexual females produce only female offspring, and you wonder why sexual female snails still exist.

“It’s not only that (the asexuals) are not making males. The asexual daughters are growing up faster too,” Neiman notes.

Before her study, Neiman thought the asexual females would bear extra costs for each additional genome because they would be chock full of metabolically expensive ingredients like RNA and proteins. Such is the case with plants, like wheat. But there was no difference in growth rate, shell length, or time to reproductive maturity between asexual females with three genomic copies and those with four, ruling out that theory.

Instead, the surprise lay in the fact the asexual females didn’t seem to pay any price whatsoever for having those extra genomes. In fact, there was no discernible disadvantage at all.

So, why do sexual female snails exist, and how do they survive when they’re co-existing and competing with asexual females?

The answer may lie in part to a parasitic worm that preys upon the snails. The asexual females are more vulnerable because their offspring’s genomes are exact replicas of their own, making them easier to target and wipe out. The sexual females, because they mate, inherit a separate, distinct genomic set that diversifies the gene pool and thus makes them better able to withstand parasitic attacks.

Still, sexual females have been found alongside asexuals in lakes without the parasitic worms, which muddies the whole idea that genetic diversity is the sole reason why sexual snails persist. Neiman seems to like it that way.

“You could argue that our genome is the most important thing we have, yet we don’t know why humans have two copies when a lot of organisms do fine with one, or three, or more,” she says. “This research speaks to that question.”  Science Daily  Original web page at Science Daily


Attention: Terrapin! Invasive pond slider on the move

Using genetic methods, scientists of the Senckenberg Research Institute in Dresden discovered that the introduced pond slider is capable of reproducing in Europe even outside of the Mediterranean region. The turtle, originally from North America, poses a significant threat to the native turtle fauna and, according to the authors of the study recently published in the scientific journal “Conservation Genetics,” should be intercepted in Europe.

The pond slider (Trachemys scripta) is the world’s most widely distributed species beyond its native range. These turtles with a shell length of up to 30 centimeters are native to the Southeastern U.S. – but today, they are found on all continents, except for Antarctica and a few oceanic islands. “The turtle can be found in the wild in practically all European countries.” explains Dr. Melita Vamberger of the Senckenberg Natural History Collections in Dresden, and she continues, “These reptiles owe their wide-spread distribution to the captive animal trade.”

The species is considered a threat to native turtles, since it is in direct competition with them regarding food as well as nesting and basking sites. Moreover, the introduced reptiles are potential carriers of parasites and other pathogens. Since the 1990s, the import of these popular pets with their vividly orange to red head stripes has been outlawed in Europe. “However, in some countries, in particular in the Balkan states, the illegal trade continues to flourish,” adds Vamberger, and she goes on to say, “But for a long time, it was not clear whether the species could become invasive in Europe.” Until now, the successful reproduction and establishment of these animals had only been documented in the Mediterranean region.

The Slovenian-German team of researchers around Dr. Vamberger and the director of Senckenberg Dresden, Professor Dr. Uwe Fritz has now been able to demonstrate by means of genetic studies that the turtles also reproduce in Slovenia. The biologists took samples of 77 turtles from three sites and could show that they reproduce in all areas examined in Slovenia. “We selected the sites based on climatic differences,” explains Fritz, and he adds, “Unfortunately, the pond slider also reproduce and spread in the vicinity of Ljubljana – a temperate, continental climate.”

For the first time, the researchers were thus able to offer genetic proof that Trachemys scripta can also reproduce outside the Mediterranean region with its mild climate. Around Ljubljana, the capital of Slovenia, fewer animals were found that were related to each other than in the warmer regions, which could indicate that the turtles reproduce less frequently here. “However, it is likely that more animals with new genetic material are being released near the city, which necessarily leads to fewer related animals,” cautions Vamberger.

Due to the potential for expansion beyond the Mediterranean region and the potential threat to native species, the sliders should be classified as invasive, according to the biologists from Dresden. “In addition, we recommend to intercept the pond slider, at least in habitats occupied by native turtle species, in order to prevent the spread of the invasive turtle and the displacement of the native inhabitants,” says Fritz in closing.  Science Daily  Original web page at Science Daily


* Reproduction, stem cell researchers set up a rescue plan for Northern White Rhino

International scientists set up a rescue plan for the last three northern white rhinos (Ceratotherium simum cottoni) on Earth. The goal is to use the remaining three rhinos and tissue samples from already dead individuals to multiply them into a viable self-sustaining population. For this purpose, scientists apply recent findings in reproduction and stem cell research.

International scientists set up a rescue plan for the worldwide last three northern white rhinos (Ceratotherium simum cottoni). The goal is to use the remaining three rhinos and tissue samples from already dead individuals to multiply them into a viable self-sustaining population. For this purpose scientists apply recent findings in reproduction and stem cell research. Under the direction of the Leibniz Institute for Zoo and Wildlife Research (IZW), San Diego Zoo Global (USA), Tiergarten Schönbrunn (Austria) and ZOO Dvůr Králové (Czech Republic) experts developed a rescue plan for the northern white rhino.

The plan is to reproduce northern white rhinos using natural gametes of the last living individuals as well as using induced pluripotent stem cells (iPS cells). The iPS cells can be gained from rhino somatic cells, for example from the skin. Subsequently, in the future, it might be possible to specifically mature the iPS cells into neurons, heart muscle cells or even gametes. If everything goes according to plan, in vitro fertilised gametes can be introduced into surrogate mothers and fertile northern white rhinos will be produced. This first use of stem cell technology in animal conservation is ground breaking. A success offers new possibilities in the fight against species extinction caused by humans.

At the expert meeting “Conservation by Cellular Technologies,” which took place from 3rd to 6th December in Vienna, international scientists from four continents came to the conclusion that the northern white rhino can only be rescued by using cellular techniques. One of the participants in the meeting, the Japanese stem cell scientist Katsuhiko Hayashi (Kyushu University), has already grown mice out of simple skin cells. An international team of researchers is now working on transferring this model of success to northern white rhinos.

Only three individuals remain after the death of Nola, a 41-year-old northern white rhinoceros at the San Diego Zoo Safari Park on 22nd November, and Nabiré, a 32-year-old female at ZOO Dvůr Králové on 27th July, 2015. The last three individuals, a male and two females, presently live at Ol Pejeta Conservancy in Kenya. Age and reproductive challenges make the possibility of natural reproduction unlikely but the DNA of a dozen individual northern white rhinos has been preserved in genetic banks in Berlin and San Diego. The experts are using this genetic information to bring back the species.  Science Daily  Original web page at Science Daily


* First puppies born by in vitro fertilization

For the first time, a litter of puppies was born by in vitro fertilization, thanks to work by Cornell University researchers. The breakthrough, described in a study to be published online Dec. 9 in the journal Public Library of Science ONE, opens the door for conserving endangered canid species, using gene-editing technologies to eradicate heritable diseases in dogs and for study of genetic diseases. Canines share more than 350 similar heritable disorders and traits with humans, almost twice the number as any other species.

Nineteen embryos were transferred to the host female dog, who gave birth to seven healthy puppies, two from a beagle mother and a cocker spaniel father, and five from two pairings of beagle fathers and mothers.

“Since the mid-1970s, people have been trying to do this in a dog and have been unsuccessful,” said Alex Travis, associate professor of reproductive biology in the Baker Institute for Animal Health in Cornell’s College of Veterinary Medicine.

Jennifer Nagashima, a graduate student in Travis’ lab and the first to enroll in the Joint Graduate Training Program between the Smithsonian Conservation Biology Institute and Cornell’s Atkinson Center for a Sustainable Future, is the paper’s first author.

For successful in vitro fertilization, researchers must fertilize a mature egg with a sperm in a lab, to produce an embryo. They must then return the embryo into a host female at the right time in her reproductive cycle.

The first challenge was to collect mature eggs from the female oviduct. The researchers first tried to use eggs that were in the same stage of cell maturation as other animals, but since dogs’ reproductive cycles differ from other mammals, those eggs failed to fertilize. Through experimentation, Nagashima and colleagues found if they left the egg in the oviduct one more day, the eggs reached a stage where fertilization was greatly improved.

The second challenge was that the female tract prepares sperm for fertilization, requiring researchers to simulate those conditions in the lab. Nagashima and Skylar Sylveste, found that by adding magnesium to the cell culture, it properly prepared the sperm. “We made those two changes, and now we achieve success in fertilization rates at 80 to 90 percent,” Travis said.

The final challenge for the researchers was freezing the embryos. Travis and colleagues delivered Klondike, the first puppy born from a frozen embryo in the Western Hemisphere in 2013. Freezing the embryos allowed the researchers to insert them into the recipient’s oviducts (called Fallopian tubes in humans) at the right time in her reproductive cycle, which occurs only once or twice a year.

The findings have wide implications for wildlife conservation because, Travis said, “We can freeze and bank sperm, and use it for artificial insemination. We can also freeze oocytes, but in the absence of in vitro fertilization, we couldn’t use them. Now we can use this technique to conserve the genetics of endangered species.”

In vitro fertilization allows conservationists to store semen and eggs and bring their genes back into the gene pool in captive populations. In addition to endangered species, this can also be used to preserve rare breeds of show and working dogs.

With new genome editing techniques, researchers may one day remove genetic diseases and traits in an embryo, ridding dogs of heritable diseases. While selecting for desired traits, inbreeding has also led to detrimental genetic baggage. Different breeds are predisposed to different diseases; Golden retrievers are likely to develop lymphoma, while Dalmatians carry a gene that predisposes them to blockage with urinary stones.

“With a combination of gene editing techniques and IVF, we can potentially prevent genetic disease before it starts,” Travis said. Finally, since dogs and humans share so many diseases, dogs now offer a “powerful tool for understanding the genetic basis of diseases,” Travis said.  Science Daily  Original web page at Science Daily


Why mice have longer sperm than elephants

In the animal world, if several males mate with the same female, their sperm compete to fertilize her limited supply of eggs. Longer sperm often seem to have a competitive advantage. However, a study conducted by researchers from the Universities of Zurich and Stockholm now reveals that the size of the animals also matters. The larger the animal, the more important the number of sperm is relative to sperm length. That’s why elephants have smaller sperm than mice.

Sperm are probably the most diverse cells in terms of size and shape and have been a continual source of fascination since their first discovery nearly 350 years ago. But why are sperm so incredibly different between species? After all, they all have the same job: to fertilize the female’s eggs. As we know from many studies, sperm competition plays a key role in the evolution of sperm. This contest occurs when a female mates with several males and their numerous sperm compete to fertilize her eggs. Longer sperm are often more competitive. Interestingly, this is more common in small rodents, such as mice and rats, than in larger animals. The rodents’ sperm are also often twice as long as those of the considerably larger carnivores, ungulates, primates or even whales. The reason for this, however, is disputed.

A new study could now help shed light on the matter. Stefan Lüpold, a new member of the Department of Evolutionary Biology and Environmental Studies, University of Zurich, and his colleague John Fitzpatrick, University of Stockholm, compared the influence of sperm competition on the evolution of sperm in 100 mammalian species. Unlike previous studies, however, they didn’t just consider sperm length, but also the number of sperm per ejaculate, which is important as the resources available for sperm production need to be shared between sperm size and number. In other words, the longer every individual sperm, the fewer of them a testicle of a certain size can produce. Earlier studies suggested that the number of sperm might be just as important as sperm length, if not even more so. After all, the more sperm a male fields against his competitors, the greater the likelihood that one of them will win.

Based on their joint consideration of sperm size and number, and with the aid of new meta-analytical methods, the two researchers now reveal that species facing intense sperm competition invest more in their ejaculates on average than their monogamous counterparts. Moreover, they discovered that whether the length or the number of sperm is more important actually depends on the size of the animals. The bigger the animal, the greater the selection pressure on the overall investments in ejaculates and the more important the number of sperm becomes compared to sperm length. This is due to the more voluminous female reproductive tract, in which the sperm tend to get lost or become “diluted.”

In larger species, sperm length or speed probably comes into effect only if a sufficient number of sperm manage to get near the egg. In smaller species, however, the distance for sperm to cover is shorter and the risk of loss much smaller, allowing the advantage of longer sperm to manifest itself. As a result, you tend to find the most complex sperm forms in small species, not in large ones. For instance, small fruit flies have the longest sperm ever described, not whales, whose sperm are less than a tenth of a millimeter long and almost a thousand times shorter than those of the flies.  Science Daily  Original web page at Science Daily


Cougars likely to recolonize middle part of U.S. within the next 25 years

A groundbreaking new study shows that cougars, also known as mountain lions and pumas, are likely to recolonize portions of habitat in the middle part of the United States within the next 25 years. It is the first study to show the potential “when and where” of the repopulation of this controversial large predator.

The study, led by researchers at the University of Minnesota and Southern Illinois University Carbondale, will be published soon in the international journal Ecological Modelling.

This is the first, large-scale population viability study on cougars. The research examined more than 40 years worth of data on demographics and geographical information on more than 3 million square kilometers to determine possible areas of population establishment. The researchers specifically looked at the female dispersal since population settlement is dependent upon the arrival of females in a given area.

“We didn’t just look at where they are now, but where they could go,” said study author Michelle LaRue, a University of Minnesota research associate in the College of Science and Engineering’s Department of Earth Sciences. “These are predictive models, but we feel that our study could be an important tool for conservation of this species and education about a large carnivore that can sometimes incite fear.”

Breeding populations of cougars are already living in the Black Hills of South Dakota, and researchers noted four breeding populations in North Dakota and Nebraska. The new study shows that cougars could be expected in the next two decades in Arkansas, Missouri and Nebraska with the potential to sustain existing populations in the Dakotas and Nebraska.

Historically, cougars were once one of the most widely distributed land mammals on earth, ranging from the Atlantic to Pacific oceans and from northern British Columbia to southern Chile. In the United States, the cougars were pushed back to the American West with the arrival of European settlers. Although they have been extirpated for more than 100 years, cougars have been reported in the middle part of the U.S. over the past two decades with more than 800 instances of confirmed cougar presence from 1990-2015.

“The reason cougars used to exist across the country and now they don’t is because of people,” said study co-author Clayton K. Nielsen from Southern Illinois University Carbondale’s Cooperative Wildlife Research Laboratory and Department of Forestry. “Now that this large carnivore is expected to come back into new areas, we need have a clear plan for education and conservation.”

The next step is to examine human acceptance and attitudes toward the repopulation of cougars, said LaRue, who is also the executive director of the Cougar Network, a non-profit research organization.

“We now have the information necessary for government agencies to plan for ecosystem-based management and societal attitudes toward the recolonization of this predator,” LaRue said. “Given that cougars are expected to inhabit areas where they haven’t been for more than 100 years, this will pose considerable challenges for wildlife managers and the general public in the future.”  Science Daily  Original web page at Science Daily


Test tube foals that could help ensure rare breed survival

The recent birth of two test tube foals in the UK, as part of a collaborative project conducted by leading fertility experts, could help benefit rare breed conservation and horses with fertility problems. The births mark the successful completion of a three-year program, the aim of which was to establish and offer advanced breeding methods that are not routinely available in the UK. The births mark the successful completion of a three-year program, led by the University of Liverpool, the University of Surrey and Twemlows Stud Farm. The aim of the project was to establish and offer advanced breeding methods that are not routinely available in the UK.

It is thought that these processes could have further use in breeds under threat of extinction and for valued horses that have died or in cases where mares or stallions have specific fertility problems.

One method, called intracytoplasmic sperm injection (ICSI), has the potential to allow greater numbers of offspring to be produced from individual mares and from stallions where sperm samples are limited, allowing breeds to continue in larger numbers. Importantly, this method could allow the embryos of rare breeds to be ‘frozen’, creating a safety net of ‘reserve animals’ should anything threaten the existing stock.

Niamh Lewis, a veterinarian researcher at the University of Liverpool, who managed the project said: “These are complex methods which are currently offered by only a very few centres worldwide. The ability to perform these techniques reliably offers new hope to help overcome various fertility issues in stallions and also provides opportunities to create offspring from valuable mares who have died unexpectedly or cannot conceive in their own right.”

The foals were born using two different advanced breeding techniques. In June this year a foal named Twemlows Simba became the first foal in the UK to be born using Oocyte Transfer, a technique that involves oocytes (eggs) being collected from a donor mare and then transplanted into a surrogate female before being fertilised.

A second foal called Twemlows Little ICSI was born earlier this month using an ICSI. This technique is already used with great success for infertile human couples and involves a single sperm being injected into an egg through a thin glass pipette to create an embryo which is then transferred to a surrogate female. In this case the egg had been harvested from the ovary of a mare that died 11 months ago and was then matured in the laboratory ahead of the procedure. If rare breed embryos can be reliably frozen, as opposed to just semen as currently archived then, in case of a crisis, the breed could be resurrected by returning the embryos to surrogate mares.

Professor Caroline Argo from the University of Surrey, who was the academic lead for the project adds: “At the moment, we can freeze stallion sperm reliably but not horse eggs or embryos. However, ICSI embryos are smaller and more robust to the freezing process. Now that this method has proved successful, it could be possible to use it more routinely and widely for the purposes of conservation.”

The project was a Knowledge Transfer Partnership, jointly funded by the government’s Technology Strategy Board and Twemlows Stud Farm, Shropshire, and encompassed a major collaborative effort, which included working with consultant clinical embryologists in human medicine.

Mr Edward Matson of Twemlows Stud Farm said: “We have always strived to stay at the forefront of horse breeding and to offer our clients the most up to date techniques which are firmly centred on good science and focus on the welfare of their animals.

“The opportunity to collaborate with academic and clinical partners has allowed us to extend our service to include these advanced techniques. Until now, clients wishing to embark on these methods were largely dependent on shipping animals to overseas clinics.

Tom Beeston, CEO of the Rare Breeds Survival Trust, said: “Breeding numbers of all our native equine breeds continue to decline, if not halted soon our gene bank may be needed to reconstitute a breed, it really is that serious. Being able to freeze embryos as well as semen will mean we can do this completely and faster. This project is by far our best hope of being able to do this soon.”  Science Daily  Original web page at Science Daily


New research shows ovarian transplants appear to be safe, effective

Women who have ovarian tissue removed, stored and then transplanted back to them at a later date have a good chance of successfully becoming pregnant, according to a review of the largest series of ovarian transplants performed worldwide.

The study, which is published in Human Reproduction, one of the world’s leading reproductive medicine journals, shows that, in some patients, transplanted ovarian tissue can last at least ten years. Furthermore, the procedure appears to carry little risk of causing a return of the disease that had prompted the removal of the tissue in the first place.

Treatment for cancer is usually the reason why ovarian tissue is removed prior to treatment in the hope that it can be transplanted back into the patient at a later date to preserve her fertility. However, there have been concerns that the transplanted tissue could contain cancer cells that might prompt a recurrence of the cancer.

Dr Annette Jensen, a doctor and PhD student in Laboratory of Reproductive Biology in the Rigshospitalet, Copenhagen, Denmark, and colleagues from the Rigshospitalet, the Odense University Hospital and the Aarhus University Hospital in Denmark reviewed the outcomes of 41 Danish women who had had a total of 53 transplantations of thawed ovarian tissue and who had been followed for 10 years to assess ovarian function, fertility and the safety of the procedure

Dr Jensen said: “Many girls and young women who have been diagnosed with a disease such as cancer now have a realistic hope of recovery and living a normal life, but the treatment for their disease can cause infertility by damaging the functioning of their ovaries. As awareness of quality of life after cancer treatment has increased and techniques for removing, freezing, storing and then transplanting ovarian tissue have developed, fertility preservation is increasingly becoming an integral part of treatment. However, as ovarian transplantation is still in its early days, its efficacy and safety needs to be investigated.”

The ovarian transplantation programme started in Denmark in 2000, and since then nearly 800 women have had tissue frozen. For this study, the researchers studied the outcomes of women who had received transplantations between 2003 and June 2014.

The average age of the women at the time the tissue was frozen was 29.8 years, and the average age when the first transplant was performed was 33. Out of the 41 women, 32 wished to become pregnant. Ten (31%) were successful and had at least one child (14 children in total); this includes one woman who is in her third trimester of pregnancy. In addition, there were two legal abortions, one because the woman was separating from her partner and the other because of a recurrence of breast cancer; a third woman experienced a miscarriage in her 19th week of gestation.

Eight children were conceived naturally following the ovarian transplantation and six children were conceived with the help of in vitro fertilisation (IVF).

For three women, it has been over ten years since they had the tissue transplanted; for six patients it has been more than eight years, and for 15 patients it has been more than five years. The remaining patients have had transplanted tissue for between six months and five years. “The full functional lifespan of grafts is still being evaluated, because many of these women have ovaries that are continuing to function,” said Dr Jensen

Three of the 41 women who received an ovarian transplant had a relapse of their cancer: two had a recurrence of their breast cancer at the site of their original tumours, and one Ewing’s sarcoma patient had a relapse. The researchers say that none of these relapses appeared to be related to the transplantation of ovarian tissue, and no cancer has developed in the transplanted tissue

“As far as we know this is the largest series of ovarian tissue transplantation performed worldwide, and these findings show that grafted ovarian tissue is effective in restoring ovarian function in a safe manner. In this series of women the pregnancy rate was about 30%. The fact that cancer survivors are now able to have a child of their own is an immense, quality-of-life boost tor them,” said Dr Jensen.

“However, it’s important that women who have received transplanted ovarian tissue continue to be followed-up. In particular, we have not performed transplants in patients who have suffered from leukemia, since the ovarian tissue may harbour malignant cells in this group of patients.”

In addition to enabling women to become pregnant, the restoration of ovarian function is also important for restoring normal levels of circulating sex hormones, which serve many other functions in the body, such as preventing menopausal symptoms.

Dr Jensen and her colleagues will continue to follow-up the Danish women. “We hope that our results will enable this procedure to be regarded as an established method in other parts of the

world, which has an important implication on how it is funded and reimbursed,” she concluded. Science Daily  Original web page at Science Daily


New science redefines remote: Even pandas global

This just in from the pandas nestled in a remote corner of China: Their influence spans the globe. In this week’s international journal Ecology and Society, sustainability scholars from Michigan State University apply a new integrated framework to the decades of work they’ve done to understand how pandas and local people in pandas’ fragile environment interact across the world.

The results, with implications far beyond panda conservation, are a bit mindboggling. From economic impacts in cities like San Diego and London to crops in Memphis to global greenhouse gases, the framework of telecoupling (socioeconomic and environmental interactions over distances) lays out a dynamic, complex view of how issues of sustainability reach across the world — and then impacts rush back. And effects spring up along the way.

Understanding the minutia is important to sustainability, says lead author Jianguo “Jack” Liu, the Rachel Carson Chair in Sustainability at Michigan State University (MSU), because policies intended to improve the world’s environment or save rare animals aren’t supposed to cause damage in other places. “In this new world of hyper connectivity, even remote areas like the Wolong Nature Reserve are connected in so many ways. If we’re going to understand the world fully, and advise policy makers well, science needs to make the big picture as specific and detailed as possible.

So Liu, the director of MSU’s Center for Systems Integration and Sustainability, and his colleagues across the United States and China, hunkered into the task of showing how pandas in the mountains of southwestern China affect the globe, and vice versa.

Their paper “Multiple Telecouplings and their Complex Interrelationships” does a deep dive into the two-way superhighway of trade, economics, physical sciences and environmental ups and downs between Wolong and the rest of the world.

For example: panda loans. The cuddly iconic bears from Wolong have gone to seven cities in five countries across the world, usually for fees and often carrying diplomatic and public relations good will in both directions. The scientists identify not just those points, but zero in on the juggernaut of people involved in negotiating and facilitating the arrangements and the economic benefits and costs — from increased donations to zoo attendance to operational and training expenses.

Then the paper dives deeper. The scientific collaborations and conservation efforts expand as the pandas span out. The carbon emissions soar as pandas get new homes. For instance, a panda pair that was resettled on loan in Edinburgh, Scotland, not only spewed out some 232,000 kg of CO2 from the Boeing 777 they took from Chengdu to Scotland, but Edinburgh didn’t have enough bamboo. That meant the jet originated in Memphis, where it loaded up on bamboo before swinging by to pick up the bears. That’s an additional 12,550 km and more than 360,000 kg of CO2. Then there are the impacts of tourist visits, additional staffing and training. At each segment of the panda’s path, more effects register, if one looks for them.

It makes any discussions of panda loans — or the future of panda loans — much richer than a simple yes/no consideration. Liu also noted that the telecoupling framework has the potential to extract important understandings from the 2008 Wenchuan earthquake that devastated much of the area in and around Wolong.

“The earthquake became almost like a natural laboratory experiment,” Liu said. “Causing tourism to instantly stop for a long time has given us a good way to understand the many aspects of conservation and tourism. Wolong has been, in good times and hard times, a wonderful place to understand many important issues in conservation, ecology and sustainability that are shared around the world.  Science Daily  Original web page at Science Daily


Mating success for the European mink

The European mink (Mustela lutreola) is one of the most endangered mammals in Europe. The reasons for its decline are the destruction of its habitat in riparian areas, competition with the alien American mink and historically, extensive hunting.

The European mink is often confused with the American mink (Neovison vison, previously Mustela vison), which has successfully established itself in Europe as an escapee from fur farms. The larger and more robust American mink has nearly completely replaced the European mink in its previous range.

Species protection projects all over Europe have so far faced the problem that European minks are difficult to breed in zoos. Captivity appears to have a negative effect on breeding success. But captive-bred individuals are needed in order to release and reintroduce the animal into protective zones. “The more we know about the physiology of European minks, the better we can respond to their needs,” says lead author Franz Schwarzenberger from the Institute of Physiology, Pathophysiology and Experimental Endocrinology at the University of Veterinary Medicine, Vienna.

Scientists from the Vetmeduni Vienna, in cooperation with the Endangered Species Research Lab of Tallinn Zoo, collected faecal samples from European mink and analysed them in Vienna. The animals are managed under the aegis of an EEP program (European Endangered Species Program). Female estrus is usually determined by vaginal cytology. The aim of the study was to assess the validity of this method and to optimise diagnosis of ovulation and pregnancy.

“Using our non-invasive method, we were able to measure female estrogen levels and generate a seasonal hormone profile. The results showed that estrogen levels are higher at the time of ovulation. Such estrogen peaks occur three to four times a year on average. The animals are polyestrous. That means, during the breeding season they are fertile in regular intervals. In the past, females which had already been mated with no success were not mated again that same year. Our results reveal that mating can occur much more often,” Schwarzenberger explains.

European minks are solitary animals and extremely territorial in the wild, only approaching each other during the breeding season. In captivity, the animals are housed in large individual enclosures. “The exact time for mating is difficult to determine in a zoo because the animals attack each other if they aren’t receptive. In order to increase the chances of fertilisation, the females are examined at regular intervals during the mating season. During mating, we also closely observe the behaviour of the animals, especially of the males,” explains Astrid Nagl, first author of the study.

The Tallinn Zoo uses vaginal cytology to predict the time of ovulation. This method does not always yield satisfactory results, however. “The data from the fecal analysis serve to augment the available information so that some females which had previously not been mated successfully also had offspring,” Schwarzenberger reports.

The reintroduction of the European mink in Austria would not be easy. “In Austria, the American mink has replaced the European mink in aquatic and riparian zones,” says Schwarzenberger. Releasing the European mink in this habitat would be tantamount to a death sentence, as the American minks would defend their territory and kill the European Mink. This makes reintroduction only possible in areas where no populations of American mink exist,” says Schwarzenberger.

About 100-120 European mink live at Tallinn Zoo. The zoo’s captive-bred animals are reintroduced to the wild on the Estonian islands of Hiiumaa and Saaremaa. Another promising reintroduction project can be found at Steinhuder Meer in northwest Germany.  Science Dail  Original web page at Science Daily


Ecologists wondering where the lions, and other top predators are

Why aren’t there more lions? That was what puzzled McGill PhD student Ian Hatton, when he started looking at the proportion of predators to prey across dozens of parks in East and Southern Africa. In this case, the answer had nothing to do with isolated human hunters. The parks were teeming with potentially tasty treats for the lions. So one might imagine that the population of lions in each park would increase to match the available prey. Instead, what Hatton and the McGill-led team discovered was that, in a very systematic way, in crowded settings, prey reproduced less than they did in settings where their numbers were smaller. Moreover, they found this same pattern in a whole range of different ecosystems.

It’s a surprising finding that suggests a level of organizational structure and function in ecosystems that had not previously been recognized. Although biologists have long known of very regular mathematical laws governing functions in the body like metabolism and growth, no study has ever shown that similar kinds of laws may exist at a whole other level: that of ecosystems globally. Some scientists are already suggesting that it may well be the discovery of a new law of nature.

“I went to high school in Zimbabwe and spent vacations in the National parks there,” says Hatton, the lead author of the study that was just published in Science. “When I began my PhD in biology at McGill, I wanted to go back and compare whole communities of African animals across protected ecosystems to see how the numbers of carnivores are related to their herbivore prey at the scale of whole landscapes. So I gathered all the animal census data I could for parks in east and southern Africa.”

When Hatton and his colleagues then started putting it all together and crunching the numbers, summing up all the carnivores (lion, hyena, leopard, etc.) and herbivores (buffalo, zebra, impala, etc.) in these parks, they found a very unexpected and regular pattern. In every park they looked at, there seemed to be a very consistent relationship of predator to prey. But not in the simple pattern they might have expected to find.

“Until now, the assumption has been that when there is a lot more prey, you’d expect correspondingly more predators,” says Hatton. “But as we looked at the numbers, we discovered instead, that in the lushest ecosystems, no matter where they are in the world, the ratio of predators to their prey is greatly reduced. This is because with greater crowding, prey species have fewer offspring for every individual. In effect, the prey’s rates of reproduction are limited, which limits the abundance of predators.”

Once they observed this pattern in one setting, the researchers then began analyzing data about food pyramids, and the relationship between predators and prey in ecosystems as varied as the Indian Ocean, the Canadian Arctic and the tropical rainforests. Over the course of the next few years they analyzed data gathered about both plants and animals from more than 1000 studies done over the past 50 years covering a range of grassland, lake, forest and ocean ecosystems around the world.

In all these different settings, they found a surprising consistency in the relation of predators to prey, and confirmation that rather than the numbers of predators increasing to match the available prey, predator populations are limited by the rate at which prey reproduce. “We kept being astonished,” said Kevin McCann, of Guelph University’s Department of Integrated Biology, one of the study’s co-authors. “This is just an amazing pattern.”

What the researchers also found intriguing was that the growth patterns they saw across whole ecosystems, where large numbers of prey seemed naturally to reproduce less, were very similar to the patterns of growth in individuals. “Physiologists have long known that the speed of growth declines with size,” said co-author Jonathan Davies from McGill’s Dept. of Biology. “The cells in an elephant grow more than 100 times more slowly than those of a mouse.”

“The discovery of ecosystem-level scaling laws is particularly exciting,” adds co-author Michel Loreau, adjunct professor in McGill’s Biology Dept. and currently at the Centre national de recherché scientifique (CNRS) in France. “Their most intriguing aspect is that they recur across levels of organization, from individuals to ecosystems, and yet ecosystem-level scaling laws cannot be explained by their individual-level counterparts. It seems that some basic processes reemerge across levels of organization, but we do not yet fully understand which ones and why.”  Science Daily  Original web page at Science Daily


Who’s your daddy? If you’re a gorilla, it doesn’t matter

New research shows rank matters more than paternity for males’ relationships with infants. Being the daddy isn’t important for male gorillas when it comes to their relationships with the kids; it’s their rank in the group that makes the difference, says new research. Researchers say this supports the theory that for most of their evolution, gorillas lived in groups with one male and several females.

Being the daddy isn’t important for male gorillas when it comes to their relationships with the kids; it’s their rank in the group that makes the difference, says new research published in Animal Behaviour. The authors of the study, from the University of California, Los Angeles (UCLA) — now with Lincoln Park Zoo in Chicago — the Dian Fossey Gorilla Fund International (Atlanta USA) and the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany) say this supports the theory that for most of their evolution, gorillas lived in groups with one male and several females.

Mountain gorillas — Gorilla beringei beringei — live in groups in the forests of central Africa. One group, or troop, of gorillas can have more than one male as well as several females. However, scientists believe that this has not always been the case; earlier in their evolution, mountain gorillas may have lived in troops with only one male and several females. For the new study, researchers tracked the way male mountain gorillas interact with infants to see if their behavior is similar to other primates that live in troops with more than one male. The results show that being the biological father does not influence the way male gorillas interact with infants, suggesting that their social structure is relatively new.

“For a long time there was an assumption that monkeys and apes didn’t know who their fathers were in groups with multiple males,” said Dr. Stacy Rosenbaum, lead author of the study from Lincoln Park Zoo, Chicago USA. “Thanks to advances in molecular genetics, we now know that’s not always true. We wanted to look at how male gorillas interact with infants to see if their behavior supports this.”

Primates like chimpanzees that live in troops with more than one male have a way of recognizing which infants belong to which males. For animals that live in groups with only one male this is not necessary, as the male is most likely the father of all the infants in the group. The researchers wanted to determine whether gorillas have evolved a way of recognizing their own offspring or father.

The researchers followed gorillas in Volcanoes National Park, Rwanda, and monitored the way the males and infants interacted. They looked at the amount of time the gorillas spent grooming each other and playing, and noted every ten minutes which gorillas were physically close to one another. They also looked at which males were dominant in the group.

The researchers analyzed more than 1500 hours of data and found that there is no evidence to suggest that gorillas recognize their own offspring or father. Instead, they found that a male gorilla’s dominance or social rank had a stronger influence on its relationships with infants; alpha males tend to be more nurturing and have stronger relationships with infants in the troop. While statistically they are most likely to be the father, many infants are also sired by other males.

“When we think of a human alpha male, we have a very specific set of cultural norms that go along with that, like aggression and not being very paternal,” said Dr. Rosenbaum. “In gorillas that’s not the case at all; dominant males are often the biggest in the group, but they are gentle and nurturing with the infants.

During the field research, Dr. Rosenbaum and her colleagues also collected sample of urine and feces from the gorillas. They are now analyzing those samples at Lincoln Park Zoo alongside their behavioral data to see if there is a hormonal component to these behaviors. “We want to understand more about humans’ evolutionary history by watching how gorillas behave. Our goal is to learn more about primate evolution generally, and great apes are particularly interesting since they are humans’ closest living relatives.”   Science Daily  Original web page at Science Daily


* First artificial insemination of Yangtze giant softshell turtle

A female Yangtze giant softshell turtle (Rafetus swinhoei) — potentially the last female of her species — has been artificially inseminated. The procedure, which brought together top scientists from China, Australia and the United States, provides a ray of hope in a continuing effort to save the world’s most endangered turtle.

The pair at the Suzhou Zoo in China, were brought together as part of a breeding program in 2008. With natural breeding unsuccessful, scientists recently artificially inseminated the female with the male’s sperm. The Turtle Survival Alliance (TSA), San Diego Zoo Global and WCS’s Bronx Zoo announced that working in conjunction with Changsha Zoo, Suzhou Zoo and the China Zoo Association, a female Yangtze giant softshell turtle (Rafetus swinhoei) — potentially the last female of her species — has been artificially inseminated. The procedure, which brought together top scientists from China, Australia and the United States, provides a ray of hope in a continuing effort to save the world’s most endangered turtle.

There are four living Yangtze giant softshell turtles remaining in existence — two in Vietnam (both thought to be males) and two in China at the Suzhou Zoo (a male and female). The male and female — both believed to be greater than 100 years of age — were brought together in 2008 as part of a captive breeding program initiated by TSA and the WCS (Wildlife Conservation Society) China program. The female was transported from the Changsha Zoo to the Suzhou Zoo through the efforts of four partners (Changsha Zoo, Suzhou Zoo, TSA, and WCS).

WCS China Reptile Program Director and coordinator of the Rafetus swinhoei breeding program, Dr. Lu Shunqing, mediated the program agreement among the partners and has coordinated the program during the past 8 years. “It now appears that artificial insemination is the only possible option for the pair of Rafetus swinhoei in Suzhou Zoo to reproduce successfully,” said Dr.Lu Shunqing. “The fate of the most endangered softshell turtle of the world is now in the balance.”

Though the two turtles have before displayed courting behavior, eggs laid by the female have been infertile. “We had to find out if the last known male in China no longer produces viable sperm due to old age or an inability to inseminate the female,” said Dr. Gerald Kuchling, organizer of the artificial insemination effort and Rafetus breeding program leader for the TSA. To determine the cause of the infertility, Suzhou Zoo, Changsha Zoo, and the China Zoo Association requested TSA assemble a team of scientists to conduct a reproductive evaluation of the male, collect semen, determine if he had viable sperm, and, if viable sperm could be demonstrated, artificially inseminate the female.

“At first we tried semen collection through manual stimulation and the use of a vibrator, but as previously found in another softshell turtle, the only way was through sedation of the male and electro-ejaculation — risky procedures due to his old age,” Dr.Kuchling said.

During the process, the male was determined to have damaged sex organs, perhaps due to a fight with another male decades ago. For this reason, the scientists believe the male incapable of inseminating the female, and therefore, fertilizing the eggs.

Dr. Barbara Durrant, Director of Reproductive Physiology at the San Diego Zoo Institute for Conservation Research said, “Normal semen parameters for Rafetus are unknown as this was the first attempt to collect and examine sperm from this species. The semen evaluation revealed that approximately half of the sperm were motile.” Based on the results, it was determined the female could be artificially inseminated. This attempt marks the first time artificial insemination has been tried with any softshell turtle species and based on results of insemination with other turtles, the odds are not good for success. With natural breeding unsuccessful however, the scientists felt it was time to explore this option. Both turtles recovered from the procedure in good condition.

“The attempts to breed this critically endangered species, and overcome obstacles to natural breeding by this global consortium of experts is a great example of international cooperation to save endangered species,” said WCS Chief Veterinarian and Bronx-Zoo based Director of Zoological Health Dr. Paul P. Calle, who worked with Chinese veterinarians on the delicate sedation process. “We are grateful to our Chinese partners at the Suzhou Zoo, Changsha Zoo, and the China Zoo Association for inviting us to work with them in our collective attempt to save this species. ”

“This was a great exploration to advance the conservation of Rafetus swinhoei, however, we cannot yet determine if the exploration was successful or not,” said Director Chen Daqing of Suzhou Zoo. The female will lay the eggs in a few weeks and in a couple of weeks after that, the scientists will know if the eggs are fertile. Listed on the International Union for the Conservation of Nature’s Red List, the Yangtze giant softshell turtle is the most critically endangered turtle in the world. Its status in the wild has long been recognized as grim, but extinction risk now is believed higher than ever. Much of its demise has been attributed to over-harvesting and habitat degradation. Fort Worth Zoo Biologist and TSA President Rick Hudson said, “The conservation world will once again be holding its collective breath until we know if this was successful. The optimism we felt back in 2008 when the pair was mating and laying eggs has slowly faded as reality sank in that this pair would not breed without intervention.” “This autumn, the female Rafetus swinhoei will be moved back to Changsha Zoo. We hope some children move together with her,” said Vice Director Yan Xiahui of Changsha Zoo.  Science Daily  Original web page at Science Daily


* Frozen semen from lions are capable to produce embryos

Scientists from Berlin successfully produced embryos from African lions via assisted reproduction. What is genuinely new is the fact that they used immature eggs that were retrieved from African lionesses. After artificial maturation these eggs were injected with lions’ sperm, previously stored in a cryobank. To surprise of the scientists from the Leibniz Institute for Zoo and Wildlife Research (IZW) the development of the lion embryos was retarded in comparison to similar embryos from domestic cats. The reproduction biologists of the IZW report about their success in in vitro maturation and fertilization by sperm injection in African lions in the current issue of the scientific magazine Theriogenology. Assisted reproductive technologies (ARTs) are becoming increasingly important for the breeding of endangered species. The establishedgenome resource banks allow the integration of cryopreserved genes in existing populations regardless of time and space. “Genome resource banks can help to solve various problems in captive breeding programmes,” says Jennifer Zahmel from the IZW. Currently individual animals have to be transported for blood refreshment. Shipping embryos or just sperm cells would also reduce a possible risk of disease transmission between Zoos. Furthermore the methods of assisted reproduction are designated to link conservation efforts in the original habitat (in-situ) and with captive breeding programs (ex-situ). In any cases, the successful use of genome resource banks requires the adaptation of assisted reproductive techniques to the species specific requirements. This includes the retrieval of gametes, culture, and cryopreservation as well as artificial insemination and embryo transfer. “These reproductive techniques are successfully applied in medical science and livestock farming a. However, a comprehensive basic research is needed, owed by considerable differences in anatomy and physiology in many endangered mammals,” explains Katarina Jewgenow, head of reproduction biology department of IZW. Feline carnivores benefit from the development of reproductive techniques in domestic cats. Until now, diverse ARTs have been developed for domestic cats. Now the challenge is to make this knowledge available for endangered felids. “The in-vitro produced embryos of the African lions proved, that the methods developed for domestic cats can also be applied to lions, even though the variations developmental speed of the embryos indicate some fascinating differences between these species,” says Lorena Fernandez-Gonzalez.

Overall 68 immature oocytes, retrieved after eight-hour transportation, were cultivated in-vitro for one and a half days in a special medium. Over one third of the eggs matured and was fertilized via intracytoplasmic sperm injection (ICSI). For this, a single lion sperm is injected directly into an egg with a micro-needle. The frozen/thawed sperm used in this study was from a lion of an European zoo, which died in 2012. Even though the sperm cells exhibited a limited viability after thawing, the fertilization of a few oocytes was successful. This was verified by embryo cleavage, although the advanced blastocyst stage was achieved as late as after nine days culture. In domestic cats blastocysts can be observed after seven days already. The reasons for the slower developmental speed remain a mystery. It could be caused by the retrieval of the gametes postmortem, the prolonged transportation of the ovaries or even simply be a species-specific feature. “The successful application of this method of oocytes maturation is of particular importance for species conservation. The retrieval of fertile eggs from animals in the wild is only possible to a limited extend. However, without eggs the assisted reproduction is impossible,” comments Jewgenow.  Science Daily  Original web page at Science Daily


* Rudimentary egg and sperm cells made from stem cells

A feat achieved for the first time in humans could be a step towards a cure for infertility. Israeli and UK researchers have created human sperm and egg precursor cells in a dish, starting from a person’s skin cells. The achievement is a small step towards a treatment for infertility, although one that could face significant controversy and regulatory hurdles. The experiment, reported online in Cell on 24 December, recreates in humans parts of a procedure first developed in mice, in which cells called induced pluripotent stem (iPS) cells — reprogrammed’ cells that can differentiate into almost any cell type — are used to create sperm or eggs that are subsequently manipulated to produce live births by in vitro fertilization. In 2012, stem-cell biologist Mitinori Saitou of Kyoto University in Japan and his collaborators created the first artificial primordial germ cells (PGCs). These are specialized cells that emerge during embryonic development and later give rise to sperm or eggs. Saitou made them in a dish, starting with skin cells reprogrammed to an embryonic-like state through iPS-cell technology. They also were able to achieve the same result starting with embryonic stem cells. Although his cells could not develop beyond this precursor stage in the dish, Saito found that if he placed them in mouse testes, they would mature into sperm, and if he placed them in ovaries, they would mature into functional eggs. Both sperm and eggs could be used for in vitro fertilization. Efforts to engineer similarly functional gametes in humans have produced PGC-like cells, but with such a low efficiency — success rate of turning stem cells into gametes — that it was difficult for others to expand on the work. Previous efforts also required the introduction of genes that would render the cells unusable in the clinic.  Nature  Original web page at Nature


Arctic conditions may become critical for polar bears by end of 21st century

Shifts in the timing and duration of ice cover, especially the possible lengthening of ice-free periods, may impact polar bears under projected warming before the end of the 21st century, according to a study published November 26, 2014 in the open-access journal PLOS ONE by Stephen Hamilton from University of Alberta and colleagues. Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems, and polar bears are vulnerable to these changes in sea ice conditions. The authors of this study used sea ice projections for the Canadian Arctic Archipelago from 2006-2100 and metrics developed from polar bear energetics modeling to gain insight into the conservation challenges for polar bears facing habitat loss. Shifts away from multiyear ice to annual ice cover throughout the region, as well as lengthening ice-free periods, may become critical for polar bears before the end of the 21st century with projected warming. Each polar bear population in the Archipelago may undergo 2-5 months of ice-free conditions, where no such conditions exist presently. Under business-as-usual climate projections, polar bears may face starvation and reproductive failure across the entire Archipelago by the year 2100. “We predict that nearly one-tenth of the world’s polar bear habitat, as much as one-quarter of their global population, may undergo significant habitat loss under business-as-usual climate projections,” said Stephen Hamilton.  Science Daily  Original web page at Science Daily



Giant tortoises gain a foothold on a Galapagos island

A population of endangered giant tortoises, which once dwindled to just over a dozen, has recovered on the Galapagos island of Española, a finding described as “a true story of success and hope in conservation” by the lead author of a study published Oct. 28. Some 40 years after the first captive-bred tortoises were reintroduced to the island by the Galapagos National Park Service, the endemic Española giant tortoises are reproducing and restoring some of the ecological damage caused by feral goats that were brought to the island in the late 19th century. “The global population was down to just 15 tortoises by the 1960s. Now there are some 1,000 tortoises breeding on their own. The population is secure. It’s a rare example of how biologists and managers can collaborate to recover a species from the brink of extinction, ” said James P. Gibbs, a professor of vertebrate conservation biology at the SUNY College of Environmental Science and Forestry (ESF) and lead author of the paper published in the journal PLOS ONE. Gibbs and his collaborators assessed the tortoise population using 40 years of data from tortoises marked and recaptured repeatedly for measurement and monitoring by members of the Galapagos National Park Service, Charles Darwin Foundation, and visiting scientists. But there is another side to the success story: while the tortoise population is stable, it is not likely to increase until more of the landscape recovers from the damage inflicted by the now-eradicated goats. “Population restoration is one thing but ecological restoration is going to take a lot longer,” Gibbs said. After the goats devoured all the grassy vegetation and were subsequently removed from the island, more shrubs and small trees have grown on Española. This hinders both the growth of cactus, which is a vital piece of a tortoise’s diet, and the tortoises’ movement. Chemical analysis of the soil, done by Dr. Mark Teece, an ESF chemistry professor, shows there has been a pronounced shift from grasses to woody plants on the island in the last 100 years. The shrubs and trees also inhibit the movements of the endangered waved albatross that breeds on the island. Gibbs said the plants make it difficult for the ungainly sea birds to take flight. “This is a miraculous conservation success accomplished by the Galapagos National Park Service,” said Gibbs, ” but there is yet more work to fully recover the ecosystem upon which the tortoises and other rare species depend.”  Science Daily Original web page at Science Daily


* Wolf mother deaths threaten pack survival but not population

In 2012, biologists at Denali National Park and Preserve noted a drop in wolf sightings following the death of a breeding female from a pack that lived along the Denali Park Road. This was one of several instances where the death of an individual wolf from legal trapping or hunting sparked widespread attention in recent years. “This isn’t the first time we have noticed that the loss of a breeding wolf can affect the fate of the pack. We thought it would be valuable to systematically look at what happens to the pack and population following the death of a breeder,” said author Bridget Borg, a University of Alaska Fairbanks biology graduate student and National Park Service biologist. Borg’s research looked at changes in wolf pack fate, reproduction and population growth following the death of breeders. “Given the park’s current low wolf densities and small average pack sizes, we are concerned about harvest of wolves from packs that reside primarily within the park,” said Don Striker, Superintendent of Denali National Park and Preserve. “The death of a breeding wolf could harm the packs that provide the greatest opportunities for park visitors to see a wolf in the wild, either through a lack of reproduction or the loss of the entire pack.” Gray wolves typically live in packs consisting of the parents and their offspring from one or more years. Turnover among young members of a pack is common as they leave to search for mates and start packs of their own. Breeding members typically spend more time in the pack and act as “social glue.” Borg and other park researchers and collaborators from UAF and the Alaska Department of Fish and Game examined data collected on 70 packs during a long-term study of wolves in DenaliNational Park and Preserve. They found that although breeder death preceded or coincided with 77 percent of the cases where packs were no longer found, the death of a breeding individual did not always lead to the end of a pack. In about two out of three cases where a breeder died, the pack continued.

“It appears that the sex of the breeder that was lost and the size of the pack prior to that loss were important factors explaining pack fate following the death of a breeder,” Borg said. “The probability of a pack continuing was less if a female died or if the pack was small prior to the death.” Borg’s data also suggests that the death of a breeder has a greater influence on a pack if the wolf died during the pre-breeding or breeding season. “We noticed that human-caused mortality rates were highest during the winter and spring, which correspond to the pre-breeding and breeding seasons for wolves,” said Laura Prugh, co-author and wildlife ecologist at the UAF Institute of Arctic Biology. “Harvest may lower the odds of pack survival because of this timing, especially when pack sizes are small.” Surprisingly, higher rates of breeder mortality and pack disruption did not correspond to lower population growth, indicating that the wolf population was resilient to loss of breeding individuals at a population level, according to the authors. They suggest that wolves may compensate for the death of breeders in a variety of ways, such as rapid replacement of breeders or increased reproductive success the following year. Although breeder loss appeared to have little effect on Denali wolves at the population level, the loss of individuals may be important at a local level. The researchers note that rates of denning and successfully raising pups decreased for packs in which a breeder died or was killed but the pack remained together. The wolf packs that successfully raise pups near the park road tend to be those seen most often by tourists. Science Daily  Original web page at Science Daily