Ancestral Numbers Game Makes Us All Related
By 30 Generations Back You Have One Billion Ancestors
Aug 1, 2008 Rosemary E. Bachelor
If you take your family back 14 generations, which would usually be more than 300 years, you have in that 14th generation 16,384 direct ancestors from whom you are equally descended. If you then add to that your ancestors in the previous 13 generations you have more than 32,400 ancestors.
Try it: two parents, four grandparents, and keep doubling the number every generation.
One Quadrillion Ancestors?
If you keep doing this, you will reach one billion ancestors in the 30th generation back, and one trillion in the 40th generation back. The 50th generation back? That's the generation in which you have reached one quadrillion ancestors. It is mind boggling!
What's amazing is that by the 50th generation we are only back to, on the average, about the year 850.
Does It Sound Wacky?
Does something about this sound wacky? You bet! The numbers are right, but the "people story" represents a quite different set of circumstances. The more generations we trace backward, the more ancestors we accumulate but, before long, there just aren't that many people on planet earth.
The present population of the world is less than 10 billion people and that's the most it has ever been. So, about the 34th generation you already have more than 17 billion ancestors. Do we have more ancestors than there are people? How can this be?
Why We're All Related
Experienced genealogists have probably started sniffing out the answer. They know that, for instance, they descend from the same person more than once. In fact, in most little colonial era towns everybody was related to almost everyone else. The gene pool was small. You might descend from Dr. Comfort Starr, Boston's first surgeon, by more than one of his wives, or from three of his grandchildren.
Here's how to picture this ancestral numbers game. Visualize a diamond. You are at the lower point and as you start upward (back in time) tracing your ancestors, the diamond (and number of ancestors) gets wider...until a point. Then the diamond starts shrinking as it continues upward towards its top point. Now we are further back in time and there are less people.
The Lesson of the Diamond
This one diamond cleverly makes two points: 1) As the world's gene pool shrinks, we are more and more descended from fewer people many times over, and 2) This is why we are all related. We descend from a very small number of people.
Get involved in the Genographic Project and learn more about our very earliest ancestors--those who lived in prehistoric times.
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