Humans and cattle go way back, but the origins of this relationship have been murky. Now scientists have shored up the controversial idea that humans domesticated cattle in Africa, not just in Near East Asia as archaeologists have believed for decades. The study, reported [12 April issue of Science ] in the 12 April issue of Science, also fills in details of how other domesticated cattle were brought into the African continent, and it could provide insights into how humans learned to produce food.
Most researchers thought the first domesticated cattle in Africa arrived from the Near East, perhaps as early as 7800 years ago. But in the 1980s, a few archaeologists began to argue that inhabitants of northeastern Africa had domesticated cattle independently some 10,000 years ago. Many thought that the evidence--poorly preserved bones--was ambiguous, and the idea languished. In the 1990s, however, further studies of the bones and cattle genetics began to make an African domestication seem more plausible. Now a team led by Olivier Hanotte, a molecular geneticist at the International Livestock Research Institute (ILRI) in Nairobi, Kenya, and J. Edward Rege of ILRI in Addis Ababa, Ethiopia, has painted the most complete picture yet of the cattle origins.
A statistical analysis revealed three major genetic trends within current cattle populations across Africa. Two influences came from outside Africa. The genetic signature of zebu--a type of humped cattle domesticated some 8000 years ago in the area of Pakistan--was most prominent in cattle in the Horn of Africa. From this, the team concluded that zebu were introduced to that region primarily through sea trade. Cattle populations across northern Africa, in contrast, contained genetic influence from taurine cattle, which were domesticated at least 8000 years ago in the Fertile Crescent of Turkey and other countries. Another sizable component of the genetic variation featured neither of these influences, leading Hanotte's team to suspect that it represents a unique domestication of native wild cattle in Africa.
A few skeptics remain. "The article does not prove an earlier independent domestication event in Africa," says Andrew Smith of the University of Cape Town, South Africa. For that, he wants to see archaeological evidence for African cattle domestication that might place it before the same achievement in Near East Asia. Fiona Marshall of Washington University in St. Louis, Missouri, however, is more impressed. To her, the new finding reinforces the idea that people living in Africa during the last 10,000 or so years took an unusual path to food production: domesticating livestock before plants.
International Livestock Research Institute