Lawrie McFarlane: Everyone is related to everyone if you go back far enough

In a recent letter to the editor, Cheera J. Crow of Brentwood Bay wrote that it’s ­nonsense to portray the British (and ­Canadian) royal family as exclusively white. She pointed out that Queen Elizabeth is said to have had several Black ancestors, among them Portugal’s Queen Charlotte (1744-1818), who stemmed from her family’s African branch.

Ms. Crow is right, but perhaps more so than she realizes, for not only does our Queen have Black ancestors, she also has Chinese, Egyptian, Mayan and Fijian ­ancestors.

article continues below

Indeed, she has relatives among every ethnic group that ever existed on our planet, and so do we all.

The math is simple, but with a surprise ending. (I’m indebted to Peter Ralph at the University of Oregon and Graham Coop at the University of California at Davis for the proof, and to science writer Ross Pomeroy for drawing attention to their work.)

It goes like this. Each of us has two ­parents, meaning that the number of our ancestors doubles with every generation.

Making an assumption I’ll come to in a moment, if we go back 10 generations, each of us should have 1,024 ancestors.

Here’s the math.

I have two parents. They each had two, making four. They each had two, making 8. Carry this on for 10 generations, and you get 1,024.

Go back 20 generations, and our ­ancestors number one million. This is just straight arithmetic.

But now the surprise ending. If we carried the math back 40 generations, we would find that each of us has a trillion ancestors. And that cannot be, because at no time has our planet ever been home to that many people.

So is the math wrong? No. However it makes the assumption that since everyone ever born had two parents, they must have had four grandparents, who in turn had 16 grandparents, and so on.

Evidently that can’t be right. The question is how.

And the only answer is that, going back in time, we’re forced to conclude there has been a huge amount of historical ­co-mingling.

Incestuous relationships must have played a part. So, too, other forms of inter-family trysts and polygamous marriages. In effect, those trillion ancestors weren’t a trillion ­separate people. Many of them were the same person, engaged in blended liaisons.

But that dramatically changes family trees. We are all far more inter-related than we thought. And we know by how much.

Although the population of the planet today is 7.7 billion, geneticists have proved that 3,400 years ago, everyone alive at that time (around 40 million) was related to ­everyone alive today. And that means we can count relatives among pretty well every ethnic group that ever existed.

As the British geneticist Adam ­Rutherford has written: “Every Nazi had Jewish ancestors. Every white supremacist has Middle Eastern ancestors. Every ­racist has African, Indian, Chinese, American Indian, and Aboriginal Australian ancestors, as does everyone else … Racial purity is a pure fantasy. For humans, there are no ­purebloods, only mongrels enriched by the blood of multitudes.”

Thus, each of us can claim some of ­history’s greatest leaders and scientists, poets and explorers among our ancestors.

But of course, it also means we are related to some of the most dreadful specimens of pure evil that ever lived.

A warning, perhaps, against placing too much importance on lineage.

Read Related Topics

© Copyright Times Colonist

Find out what's happening in your community.