Friday, May 1, 2009

Garden of Eden: The Origin Of Modern Humans

A new genetic survey by Dr. Sarah A. Tishkoff of the University of Pennsylvania and her team has found that modern humans originated in an area between Namibia and Angola, on the coast of southwest Africa. Read the New York Times Article: Eden? Maybe. But Where’s the Apple Tree?

However, this harsh and inhospitable area is nothing Eden-like, they said. The origin of a species, like modern humans, is generally pinpointed to a place where its individuals show the highest genetic diversity. After comparing genetic data from populations around the world, the researchers pinpointed the population with the highest genetic diversity - somewhere on the coast of southwest Africa near the Kalahari Desert. The Bushmen or San people currently call this area their home.

The researchers have also calculated the exit point of modern humans that left Africa about 50,000 years ago. The exit point lies in an area of the African coast of the Red Sea. If the "Out Of Africa" theory holds true, this tribal group of about 150 people that left Africa at that exit point displaced other archaic Homo sapiens populations from different continents, giving rise to the current modern human populations.


3 comments:

zacharoo said...

The presence of genes that, according to models of given analyses, came from outside of Africa, earlier than 200ka (such as MCPH1) are real wrenches in the gears of strict out-of-Africa ("Eve Theory"). Plus, from my (limited) understanding of how population genetics works, these models all assume that genes under study are neutral, and that assumption is not always valid (mtDNA has been proposed to be target of selection).

So I think genetic and morphological evidence does point to Africa as the chief contributor to modern humans as we (think!) we know them today. However, I would be surprised if all populations were 'replaced'. Quite probably many 'archaic' (whatever that really means) populations were replaced, but certainly not all of them. Hasn't the frequency of shovel-shaped maxillary incisors been high in E. Asia for over a million years?

Raymond Ho said...

Right ... as a matter of fact, shovel shaped incisors are still being used as indicator that an individual has Asian origins, and was used to linked Native Americans (I think) and also Eskimos to Asian population.

Anonymous said...

More archeological evidence keep coming up indicating Africa as the cradle of Man....The African Eve theory is not far fetched at all because if any one has studied the human genetic mutation,you will realize that,someone who has lived longer has a higher rate of genetic mutation..and this was illustrated by Sarah Tishkoff perfectly.