May 29, 2008 - DNA tells the history of mankind

For our 25th wedding anniversary, I gave my wife a framed version of a beautiful photograph she took of a pond in Berlin.

She asked what I wanted. I said I wanted to have my DNA tested. After 25 years, I said, you deserve to know who I am.

So she ordered the testing kit from National Geographic's Genographic Project (see www.nationalgeographic.com/genographic), and I dutifully swabbed the inside of my cheeks with the scraper. It will be some four to six weeks before I hear back. It cost about $100.

So those rumors about Indian ancestry -- truth or myth? Are there any other surprises? I chose to follow the paternal line (my paternal grandmother's father was supposed to be full-blooded Cherokee).

National Geographic also sent a quite wonderful DVD about the genetic history of the human race. Dr. Spencer Wells is a most engaging host, who gallivants around the globe exploring and explaining human genetic change.

Here's the broad thesis of modern genetics: we are all Africans.

A single genetic pool -- the San Bush people (the only people to use the "clicking" language) -- is a small and handsome tribe from east central Africa. Some 60,000 years ago some of them left their homeland, possibly because of drought. We know this: the oldest surviving strands of our genetic history (especially mitochondrial DNA, which goes back another 40,000 years) are in their neighborhood.

The next archaeological evidence of early humans appears in ... Australia! That's a little surprising -- it's 10,000 kilometers of water away. Rolling back the genetic clock and matching it to the global history puts that at a time when glaciers had sucked up a lot of water. The migration probably followed coastal routes (Africa to Middle East to India to west Pacific) that are now back underwater, so there's no intervening evidence.

But there was a final 250 kilometers of travel over water from Malaysia to Australia -- about which I can only say, "these people REALLY wanted to get away from their parents."

The DVD that National Geographic sent me is fascinating. This geneticist goes to Australia, where he is told by an aborigine that we westerners may wonder where we came from, but his people KNOW. They came from Australia.

But in an obscure, isolated village in India, there's a distinct genetic marker -- tracing back to Africa, and inherited by all Australian aborigines. But there are no Australian genetic mutations that show up traveling the other way (from there to anywhere else).

Conclusion: Australians are Africans.

There's another migration: Africa to the Middle East. From thence, to India again, and northeast (following migratory paths of animals) to central Asia.

From there, the genetic history of mankind abruptly forks: west to Europe (to move into lands where the glaciers had receded) and northeast again into Asia, thence to the Bering Strait, and over the land bridge to the Americas. That would be where my Cherokee DNA marker shows up -- or not.

The way this works is that my sample will now be nothing more to National Geographic than a coded number. And I'm the only one who knows the code, so it's anonymous. But I can look at that data, unlocking it with my private code, and follow all the migratory paths of my fathers. (It's another $100 to track your mother's DNA.)

I swear there is something in us -- collective unconscious, genetic memory, or something else entirely -- that remembers all these roads.

But I feel this deepening understanding in a way I haven't before: we really are just one family. It's pretty cool to have proof.

--
LaRue's Views are his own.