It might come as quite a surprise to you to learn, but everyone on earth is - mathematically and genetically at least - related to every other single person on the planet, if you go back far enough.
Sure, we can attempt to wrap our heads around that fact and it might not seem that far-fetched, but the actual number behind it are quite mind-blowing.
Right, he we go.
In 2013, Peter Ralph from USC Dornsife - a university in Southern California - used maths, statistics, and data analysis of genomic data to learn about human demographics and evolution.
Alongside Graham Coop, a University of California geneticist - they put together a DNA based proof that everyone on earth is related to every other person, somewhere down the line.
Let's have Ralph explain it himself.
Speaking to phys.org, he said: "The fact that everyone has two parents means that the number of ancestors for each individual doubles every generation.
"By using basic mathematics, we can calculate that ten generations ago each individual had a thousand ancestors, and 20 generations ago they had a million and so on."
Here's the interesting part.
He continued: "But when we get to 40 generations ago, in the time of Charlemagne, we arrive at a trillion ancestors and that is a problem because we now have more ancestors than there were people.
"Thus one can deduce that a lot of those ancestors must be the same person."
Consider, if you will, a family tree.
Ralph explained: "At first it does look like a tree, with the branches doubling every generation, but then pretty soon the branches start running into one another and it begins to resemble more of a web-like tapestry as distant cousins marry and share a set of distant grandparents.
"That means that although hardly anyone marries their cousin in Western Europe, many people are unwittingly marrying their 30th cousin."
This research built on a 1999 paper by Yale statistician Joseph Chang that concluded that we all must share a common ancestor and that 'all individuals who have any descendants among the present-day individuals are actually ancestors of all present-day individuals'.
Mind-blowing stuff, really.
Ralph and Coop focused their genetic research on just Europe, and managed to confirm Chang's assertions.
Ralph added: "The length of a shared DNA sequence shows how closely, or distantly, two people are related.
"Thus DNA sequences shared with parents are the longest, those shared with grandparents are half as long and those shared with great-grandparents half as long again and so on.
"So the longer ago an ancestor is, the shorter the chunk is likely to be."
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"Our research confirmed what Chang suspected-that everybody who was alive in Europe a thousand years ago and who had children, is an ancestor of everyone alive today who has some European ancestry."
This is, obviously, more than a little bit confusing, but lends itself to support the idea that everyone has common ancestors, and that the all-ancestor generation lived about 3,400.
That means that, whilst you shouldn't assume you're marrying your first cousin - unless you live somewhere with very little interaction with other areas of the world - you should know that everyone else in the world is - if only distantly - in some way related to you.
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