Veronique Greenwood runs down research showing just how much our genealogical pasts converge:
Chances are, if you have a famous ancestor far enough back that finding out about them is a surprise, you share them with a small city of other people. And the farther back you go, the truer that is. In 2004, statistician Joseph Chang, computer scientist Douglas Rohde, and writer Steve Olson used a computer model of human genetics to show that anyone who was alive 2,000-3,000 years ago is either the ancestor of everyone who’s now alive, or no one at all. Think about that: If a person alive in 1,000 BCE has any descendants alive today, they have all of us—even people from different continents and isolated populations. This line of thought led to the revelation that everyone of European heritage alive today is a descendant of Charlemagne, who ruled over much of Europe as the first Holy Roman Emperor. As science writer Carl Zimmer wrote last week, it’s “Charlemagne for everyone!” (Zimmer’s excellent post covers a recent paper that looked at actual genomic data from European populations and came to a similar conclusion: All living Europeans, from Turkey to England, Spain to Finland, are related many times over.)
She sees our sameness as an asset:
Given that people—especially those in melting-pot countries with only a vague sense of where they came from—often search out their genealogies to find their special background, this information might be a bit disconcerting. Everyone’s genomes and families are not as enduringly specific as we tend to think. But while genetics doesn’t reflect much of our imagined genealogical uniqueness, it’s shown that we’re more closely tied to our species as a whole than we might have realized. We’re all part of this enormous human fabric, full of fascinating tendencies and bizarre biochemistry. And research is revealing more and more about humanity as a whole and our incredibly beautiful, incredibly unlikely perch in the universe. That’s a tradition to be proud of.