Anaheim, Calif. -- Genetic diversity in Africa is extremely high, even between closely related or located groups and much higher than diversity in other human populations. This diversity suggests a recent African origin for modern humans and a raft of potentially fertile medical research, according to a Penn State evolutionary biologist.

"Africa has been greatly underrepresented in studies of genetic diversity compared with European and Asian populations," says Dr. Sarah Tishkoff, postdoctoral research fellow in biology. "This is not only important in determining where, when and how modern humans evolved, but also in understanding genetic diseases of Africans and African Americans and in identifying potential treatments for diseases like malaria and HIV."

Tishkoff; Andrew Clark, Penn State; Kenneth Kidd, Yale University; Giovanni Destro-Bisol, University "La Sapienza," Rome, and Himla Soodyall and Trefor Jenkins, WITS University, South Africa, looked at three locations on DNA samples from 13 to 18 populations in Africa and 30 to 45 populations in the remainder of the world.

"We found an enormous amount of diversity within and between the African populations, and we found much less diversity in non-African populations," Tishkoff told attendees today (Jan. 22) at the annual meeting of the American Association for the Advancement of Science in Anaheim. "Only a small subset of the diversity in Africa is found in Europe and the Middle East, and an even narrower set is found in American Indians."

The researchers were looking at genetic information that is inherited from both the mother and the father, and exists on a strand of DNA close enough together so that the markers are transferred intact.

"Using these markers to trace lineages, we find that modern humans appear to have emerged from Africa between 100,000 and 150,000 years ago and the population that left Africa was rather small," says Tishkoff
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Contact: A'ndrea Elyse Messer
aem1@psu.edu
814-865-9481
Penn State
22-Jan-1999