Everyone on earth is a blood relative of every other

Feargal Mooney

The reason that everyone who investigates their roots comes up with some royal connection is that we are all descended from the same people. Look at it this way: go back generation by generation; each person has 2 parents, 4 grandparents, 8 great grandparents etc. The "problem" is that with only a few more generations you get numbers turning into zillions - more than the total number of people who ever lived. The reason why there were not really zillions of ancestors is that we share our ancestors with other people.

When we step back through the generations, we find that there were less and less people alive, not more. Now of the people who were alive in the past, say in Europe around 1400, about 20% of them have no living descendants. Of the other 80% every person alive in Europe today shares one of them as an ancestor. In other words everyone in Europe today shares a common ancestor who lived in 1400.

Okay, regress further back. According to The Royal We by Steve Olson, writing in the Atlantic Monthly of May 2002:

"... the most recent common ancestor of all six billion people on earth today probably lived just a couple of thousand years ago. And not long before that the majority of the people on the planet were the direct ancestors of everyone alive today. Confucius, Nefertiti, and just about any other ancient historical figure who was even moderately prolific must today be counted among everyone's ancestors."

There is another interesting implication, referred to at the end of the article. If we look forward in time, it will be the case that at some time in the distant future every one of us will either have no descendants at all, or else will be an ancestor of every single person born.

If you find this hard to believe, you will have to disprove the maths of Joseph Chang, a statistician at Yale University. These are his findings, and as the article says, "The mathematics of our ancestry is exceedingly complex."