Cattle aren't known for their intelligence. Perhaps it's because their family tree has a very skinny trunk.
Genetic evidence suggests all "taurine" cattle (the most commonly recognized breed) descend from only about 80 females and came from a single region in what is now Iran about 10,500 years ago. A study in the journal Molecular Biology and Evolution traced the modern global herd's heritage back to its ancestral home on the range.
The study compared mitochondrial DNA extracted from 15 preserved ancient cattle's bones to modern cattle and found little variation. Little variation meant the founding population didn't have many different versions of the mitochondrial genes to start with.
Earlier research published in PloS ONE suggested that taurine cattle may have later received a small genetic boost from European aurochs. Aurochs were the super-sized ancestors of our modern hamburger on the hoof.
The size and nasty disposition of the wild auroch (Bos primigenius) would have made it a formidable beast to tame for the ancient Iranians. That difficulty is possibly why domestication only occurred with a small number of animals. The authors of the paper in Molecular Biology and Evolution suggested that only humans who had settled down into villages would have had the ability to domesticate the auroch.
"Importantly, the two sites showing the earliest signs of the wild auroch's domestication — Dja´de and Çayönü — are less than 250 kilometers (155 miles) apart," wrote the multinational group of authors led by Ruth Bollongino of the University of Mainz, Germany.
"Interestingly, archaeological signs of sedentism during the 9th millennium B.C. are restricted to the same region," according to the paper. "It is conceivable that the management of wild cattle was too challenging for the mobile population of the surrounding mountainous areas where goat was the preferred domestic species."
But not all the world's mooing milk-makers have the same mom. Only the taurine cattle were domesticated in the Middle East.
Taurine cattle (Bos taurus) are the docile cows and raging bulls common to Wild West films. Humped cattle (Bos indicus), or zebu, which roam India, are thought to have arisen from a separate domestication of an auroch subspecies in what is now Pakistan or India.
Aurochs went extinct due to habitat loss, hunting and other pressures. The last individual died in the Jaktorów Forest of Poland in 1627.
Top photo: A curious cow. Credit: iStockPhoto.
Bottom photo: A Heck cow, the result of an attempt to breed the auroch back into existence from cattle. Credit: Wikimedia Commons.