It looks like ol' Bessie and 1.4 billion of her kin are the result of a genetic bottleneck. European researchers are claiming that the hoards of domestic cattle that exist today are descended from a small group of Eurasian wild ox called aurochs that roamed the Near East 10 millenia ago. In their genetic study, published this month in Molecular Biology and Evolution, scientists from France, Germany, and the United Kingdom compared mitochondrial DNA of 15 Neolithic to Iron Age Iranian cattle to sequences from modern domestic bovines to determine that 80 or so female aurochs were domesticated about 10,500 years ago and gave rise to today's millions of domestic cattle.
"This is a surprisingly small number of cattle," said University College London geneticist and study coauthor Mark Thomas in a press release announcing the results. "We know from archaeological remains that the wild ancestors of modern-day cattle were common throughout Asia and Europe, so there would have been plenty of opportunities to capture and domesticate them."
Hoof tip to Wired Science.