WASHINGTON — Human beings may have had a brush with extinction 70,000 years ago, an extensive genetic study suggests.

The human population at that time was reduced to small isolated groups in Africa, apparently because of drought, according to an analysis released Thursday.

The report notes that a separate study by researchers at Stanford University estimated the number of early humans may have shrunk as low as 2,000 before numbers began to expand again in the early Stone Age.

"This study illustrates the extraordinary power of genetics to reveal insights into some of the key events in our species' history," Spencer Wells, National Geographic Society explorer in residence, said in a statement.

"Tiny bands of early humans, forced apart by harsh environmental conditions, coming back from the brink to reunite and populate the world," he added. "Truly an epic drama, written in our DNA."

Wells is director of the Genographic Project, launched in 2005 to study anthropology using genetics. The report was published in the American Journal of Human Genetics.

Previous studies using mitochondrial DNA — which is passed down through mothers — have shown that all modern humans share one female ancestor (out of thousands), the "mitochondrial Eve," who lived in Africa about 200,000 years ago.

The migrations of humans out of Africa to populate the rest of the world appear to have begun about 60,000 years ago, but little has been known about humans between mitochondrial Eve and that dispersal.

The new study looks at the mitochondrial DNA of the Khoi and San people in South Africa, formerly known as Hottentots and Bushmen, who appear to have diverged from other people between 90,000 and 150,000 years ago.

The researchers, led by Doron Behar of Rambam Medical Center in Haifa, Israel and Saharon Rosset of IBM T.J. Watson Research Center in Yorktown Heights, N.Y., and Tel Aviv University, concluded that humans separated into small populations prior to the Stone Age, when they came back together and began to increase in numbers and spread to other areas.

Eastern Africa experienced a series of severe droughts between 135,000 and 90,000 years ago, and the researchers said this climatological shift may have contributed to the population changes, dividing into small, isolated groups which developed independently.

Paleontologist Meave Leakey, a Genographic adviser, commented: "Who would have thought that as recently as 70,000 years ago, extremes of climate had reduced our population to such small numbers that we were on the very edge of extinction?"

Today more than 6.6 billion people inhabit the globe, according to the U.S. Census Bureau.

The research was funded by the National Geographic Society, IBM, the Waitt Family Foundation, the Seaver Family Foundation, Family Tree DNA and Arizona Research Labs.

It sounds like more left wing propoganda.

Yeah, those damn smart people and their annoying knowledge.

That's really cool stuff.

(Diehard, I know you were kidding.)

Is he? I'm not sure he is.

explaining mitochondrial dna testing to diehard is a losing cause. Anything that erodes away his fundalmentalism is put in a category of left wing propaganda.

Very interesting, indeed.

And Diehard, if anything, it would be more Christian Coalition than "left-wing propganda". In terms of left & right, I think this article travels about as far left as Mike Huckabee does.

jest alert for the chronically outraged...



Sounds like Right wing propaganda to me.

"Look!!!
The earth has it's own natural cycles!!
This is just one of them.

And the earth recovered from it!!
Without a carbon tax!!!

WSS

I took a Philosophy of Science class at John Carroll. If it were not for the teacher I would have forgot the class and sold back the book. Turns out the professor was awesome and I kept the book.

Besides quantam physics and paradigm shifts, I learned that every 150,000 years the Earth has an extiction, or malady.

We're on the edge of that 150K years now.