Kate Riley / Times staff columnist
Out of Africa, and beyond
All of the world's people have immigration in common.
We or our forebears, recent or ancient, came from somewhere else — with one region's exception. Science tells us we are all out of Africa. The first mother common to all of us lived and died there as long as 170,000 years ago.
But we are all much more closely related than that, according to some scientists.
Last year, the National Geographic Society launched a five-year project to collect DNA samples from more than 100,000 indigenous people all over the world. By tracking the changes in mitochondrial DNA and the Y chromosome, Genographic Project scientists are tracing the timing of how people moved out of Africa, into Asia and Europe and beyond.
I was interested because I've been researching issues related to Kennewick Man, the 9,300-year-old remains found on the Columbia River shore. That story is rife with ancient immigration controversies: Modern Columbia Plateau tribes who claim him say they came out of the earth. Scientists who have studied the remains suggest a possible connection to Southeast Asia.
Intrigued with the larger project, I sent for the $95 kit (proceeds support the project) and sent back a DNA sample.
I am unremarkable, it turns out — a member of something calledHaplogroup H, a characteristic shared by about 40 percent of European inhabitants.
I like to think about the long line stretching between Mitochondrial Eve and me. According to my personal map, my many-greats-grandmother searched for seeds in what is now Iraq or Syria 60,000 years ago. Then there was great-great-great-grandmother Mary Walls Kavanagh fretting over new ways to prepare the potatoes she dug from behind her County Kilkenny, Ireland, cottage, in the 1850s. Now there's me as I cruise the bountiful grocery produce department and still have no clue what to make for dinner.
But there's a limit to this information. People get their mitochondrial DNA from their mothers, so the Genographic Project traces my family back only through my mother's mother's mother and so on. Men have two lines of information, since they also inherit their father's Y chromosome. My brother's test would show our father's father's father's — and so on — chain.
Still, that leaves out the majority of our ancestral lines. What about my mother's father? Or my feisty Norwegian great-great-great-great-grandmother on my father's side? According to family lore, she was milking cows in 1814 when her husband returned from Denmark after eight years in the Gunboat War. Startled, she told him, "You can kiss the cows' behind."
That's my dad's side. Stoic Norse stock with some dry humor thrown in.
The truth is, none of our family trees looks like an oak with well-defined branches. Rather, they are more like wildly tangled stands of blackberries.
Joseph Chang, a Yale University statistics professor, was troubled by all the ancestors left out by these singular chains of ancestry. He, Douglas L.T. Rhode and Steve Olson published a 2004 paper in Nature concluding the world's people have a common ancestor as recently as 3,000 years ago.
Bear with me. The math is easy at first, then quickly boggles the mind. You have two parents, four grandparents, eight great-grandparents, 16, 32, 64, 128, 256 and so on. Go back 20 generations — or only 500 years, assuming 25-year generations — and you could have 1 million distinct ancestors.
Seen the "Da Vinci Code"? The fictional movie suggests Jesus, who lived 80 generations ago, has two living descendants. Truth is, he could have billions.
Where does that leave Kennewick Man? He lived three times as long ago as Chang's theorized common ancestor. I asked the statistician what the oceans that limited mixing of peoples between hemispheres did to his conclusions. He concedes the common ancestor might be further back.
But: "At least there's plenty of time for Kennewick Man to have become the ancestor of everyone in North and South America" by the point of European contact with early Americans, Chang said.
So Kennewick Man could be an ancestor to every native group in this hemisphere and, given marriage with later immigrants, his descendants could be running around Europe, Africa and Asia by now.
That explains the international fascination with Kennewick Man's story. We are all related at some point in the distant past — and chances are many millions or more of us are related to those old bones.
Kate Riley's column appears regularly on editorial pages of The Times. Her e-mail address is firstname.lastname@example.org
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