Thursday, May 12, 2005

ENV: Finding new families, Part II

DNA Study Yields Clues on Early Humans' First Migration
By NICHOLAS WADE, May 13, 2005, The New York Times,

By studying the DNA of an ancient people in Malaysia, a team of geneticists says it has illuminated many aspects of how modern humans migrated from Africa.

The geneticists say there was only one migration of modern humans out of Africa; that it took a southern route to India, Southeast Asia and Australia; and that it consisted of a single band of hunter-gatherers, probably just a few hundred people strong.

Because these events occurred in the last Ice Age, when Europe was at first too cold for human habitation, the researchers say, it was populated only later, not directly from Africa but as an offshoot of the southern migration. The people of this offshoot would presumably have trekked back through the lands that are now India and Iran to reach the Near East and Europe.

The findings depend on analysis of mitochondrial DNA, a type of genetic material inherited solely through the female line. They are reported today in Science by a team of geneticists led by Dr. Vincent Macaulay of the University of Glasgow.

Everyone in the world can be placed on a single family tree, in terms of their mitochondrial DNA, because everyone has inherited that piece of DNA from a single woman, the mitochondrial Eve, who lived some 200,000 years ago.

There were, of course, many other women in that ancient population. But over the generations, one mitochondrial DNA replaced all the others through the process known as genetic drift.

Read the rest here . . .


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