We are all Cousins

clay county histories

Our cousin Sam Wai

Markus Krueger | Program Director  HCSCC

I work in a museum with a Viking ship, so I often hear people brag that they can trace their family back to this or that medieval king. It’s very difficult to follow a family line back more than a couple hundred years, so their scholarship impresses me. But it’s nothing special to be descended from a particular king 1000 years ago. I’m descended from that same king and so are you and probably everyone you know.

Every generation back, we have exponentially more biological ancestors. You have two biological parents, four grandparents, eight great-grandparents, then 16, 32, 64, 128…and so on. On average, there is a new generation in your family every 25 years. For us, 1000 years ago is 40 generations (give or take a few – each family is different). Two to the 40th power is more than a trillion people. But how can you have a trillion ancestors living in the year 1000 when the US Census Bureau estimates there were only 345 million people alive on earth? According to Genetic Genealogists, most of those 345 million people are your grandmas and grandpas countless times over.

Crunching the numbers, many Genetic Genealogists believe that everyone living in Europe 1000 years ago either has no living descendants today or they are the common ancestor of every single living person who can trace their family back to Europe. So for instance, I never had kids, so in 1000 years, nobody is going to be directly descended from me. But I’m gonna be everybody’s great-(times 40)-uncle, because my sister has three kids, and odds are she’s gonna be a great-grandma of everybody on earth.

Genetic Genealogists talk about the “Identical Ancestors Point” (IAP) – the most recent point in history when every individual then living is either the ancestor of every single person on earth today or of nobody. That year is very controversial. Mathematical estimates vary between 15,000 years ago to as recent as about 2000 BC. 

Though we have not compared family trees, Clay County Archivist Mark Peihl and I are cousins countless times over because we both have family from the Danish island of Bornholm. Go back far enough and I’m related to everybody from that island. Farther back than that, I’m related to everybody in Denmark, in Scandinavia, in Northern Europe, in Eurasia, in the world.

I wonder how far back I have to go before I share a grandma with my friend Sam Wai. Sam’s family is from Hong Kong and I am unaware of my Chinese ancestors, but both of us had a couple hundred million grandmas and grandpas running around Eurasia 1000 years ago, so our families – and your family – are bound to overlap.

But what about those isolated tribes in the Amazon? Genetic Genealogists argue that those folks are not as isolated as we think. The “Old World” and the “New World” have been interacting for half a millennium. All it takes is one person in that tribe to swap some genetic information with a stranger sometime in the last 500 years for the whole tribe’s family tree to soon circle back to Africa and Eurasia. 

Humans have always been interconnected. We are a social animal. It runs in our family.   

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