From the annual meeting of the American Association for the Advancement of Science in San Francisco
Genetic analysis of livestock suggests our ancient ancestors in Asia and in Europe achieved simultaneous farming feats – the domestication of pigs, sheep, water buffalo and cattle. Dr. Daniel Bradley from the Smurfit Institute, Department of Genetics, Trinity College, Dublin, Ireland, studied the mitochondrial DNA of modern cattle, and concluded that their ancestors were domesticated twice, at two sites separated by thousands of miles. His recent analysis of DNA data from modern pigs, sheep and water buffalo has thrown up the same differences in the genetic profiles of animals in different parts of the modern world.
The DNA data suggest that cattle were domesticated between 8,000 and 10,000 years ago in the Fertile Crescent of the Levant (which stretches through Turkey, Jordan and Iraq) and in the Indus valley. The goat was the first animal to be domesticated in the same region, less than 10,000 years ago, followed by sheep. Pigs were domesticated in the Fertile Crescent, and probably in China, while the water buffalo was first domesticated in southern China and at another as yet unidentified location further west.
Bradley’s team looked at mitochondrial DNA, Y chromosomes and microsatellites. All three sets of data threw up striking differences between groups of animals living in different parts of the world. Bradley concludes that the animals descended from two separate groups of common ancestors, domesticated at roughly the same time.
Edwards, C.J., Gaillard, C., Bradley, D.G., MacHugh, D.E. (2000) Y-specific microsatellite polymorphisms in a range of bovid species. Anim. Genet., 31: 127-130.
Nijman, I.J., Bradley, D.G., Hanotte, O., Otsen, M., Lenstra, J.A. (1999) Satellite DNA polymorphisms and AFLP correlate with Bos indicus-taurus hybridization. Anim. Genet., 30: 265-273.
17 February 2001
The TOOLS section of the forthcoming issue of VETERINARY SCIENCES TOMORROW will feature an article by Hans Lenstra on species identification in animal products.