June 11, 2012
This month, Smithsonian looks at the origins of the chicken, tracing the domesticated version of the bird to either India or Southeast Asia. The magazine has also explored the beginnings of the house cat in the Near East. Here’s a brief look at where other domesticated animals got their start.
Dog: Descended from the grey wolf, the dog became man’s best friend tens of thousands of years ago. The earliest known dog fossils come from a site in Belgium dating to more than 31,000 years ago. But a 2010 genetic study suggests modern dogs probably come from the Middle East: Dog DNA best matches the DNA of wolves from that part of the world. Although dog fossils date to as many as 31,000 years ago, the most ancient dog breeds around today—such as the Afghan hound, Siberian husky, chow chow and Shar Pei—are no more than a few thousand years old. And most modern dog breeds are only a couple of hundred years old, originating during the Victorian era of the 19th century.
Goat: Modern goats stem from six maternal genetic lineages, but most of today’s farm goats arose from just two domestication events: one in southeastern Turkey 10,500 years ago and another in the southern Zagros Mountains and Central Iranian Plateau almost 10,000 years ago. A 2008 genetic study of domesticated goats and their ancestor, the bezoar, indicates almost all of today’s goats (perhaps as many as 90 percent, according to one study) descend from those that originated in Turkey.
Sheep: Along with goats, sheep were among of the first hoofed animals to be domesticated, about 11,000 years ago. The animals were originally bred for their meat, and it wasn’t until about 5,000 years ago that they were also raised for wool. Archaeological and genetic evidence points to the Fertile Crescent as the original home of sheep. But researchers have discovered at least five distinct genetic lineages, indicating the animals were probably domesticated several times from various wild sheep ancestors such as the mouflon.
Cow: Domesticated cattle come in two main varieties: Taurine cattle are the common dairy and beef cattle found in Europe, North America and other cool environments. Zebu, or humped cattle, are found in warmer, tropical climates. The Taurine evolved from wild ox somewhere in the Fertile Crescent about 10,000 years ago. Research published earlier this year estimates the original population consisted of just 80 female oxen—a sign that the domestication occurred in a restricted region of the Middle East. European wild ox contributed to the cattle gene pool later, when farmers brought cattle to the continent from the Middle East. Zebu cattle can be traced back to the Indus Valley of India.
Pig: Humans domesticated pigs from wild boars several times in several different places. The earliest evidence comes from Cyprus, where fossils reveal that humans brought wild boars to the island by 12,000 years ago. Full-fledged pigs appear in the Fertile Crescent by 9,000 years ago. Genetic evidence indicates pigs also arose separately in East Asia, Southeast Asia, India and Europe. In Europe, however, the first pigs were migrants that came over with farmers from the Middle East. Later, these foreign pigs were replaced by home-grown pigs domesticated from local European boars.
Horse: Last month, researchers reconstructing the population genetics of horses confirmed humans first tamed the equines somewhere in the western part of the Eurasian Steppe. The earliest fossil evidence comes Kazakhstan when the area was inhabited by people of the Botai culture. Horse teeth dating to 3,500 B.C. show the characteristic damage that develops from biting a harnessing bridle. And chemical analyses of fatty acid residues on pottery indicate the Botai were consuming horse milk.
Donkey: The domestication of the donkey allowed people to develop mobile forms of pastoralism, enabled long-distance trade and aided in the rise of early Egypt. Modern donkeys belong to one of two distinct genetic groups, implying the animal was domesticated twice. DNA points to both events happening around 5,000 years ago in Northeast Africa. Last year, researchers determined one group descends from the Nubian wild ass. Scientists had thought the Somali wild ass was the ancestor of the second donkey clan, but DNA shows that’s not possible. Scientists have yet to pinpoint the form that gave rise to this donkey group.
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