#pedigree collapse

[sehallblog]

Pedigree Collapse: Are We All Cousins?

Have you ever thought about how many ancestors one person could possibly have? Mathematically speaking, taking one’s family tree out thirty generations would result in about a BILLION ancestors. Taking it out forty to fifty generations would result in approximately a TRILLION ancestors — more people than have EVER lived on the earth! Of course, that has never happened (or ever will), but why is…

Pedigree Collapse: Are We All Cousins?

[princesadulcinea]

If we go back 100 generations and if each generation doubles the number of ancestors:

1 generation back: 2 ancestors (your parents)

2 generations back: 4 ancestors (your grandparents)

3 generations back: 8 ancestors

4 generations back: 16 ancestors

And so on...

After 100 generations, the number of ancestors in that generation alone is:

≈1,267,650,600,228,229,401,496,703,205,376

Total number of ancestors from all generations combined (from the 1st to the 100th generation):

≈2,535,301,200,456,458,802,993,406,410,752

😱😱😱

To put it in perspective, the theoretical number of ancestors 100 generations ago is so large that it surpasses:

The total number of humans who have ever lived (about 117 billion).

The number of grains of sand on all Earth’s beaches.

This number is mind-blowingly large—much larger than the total number of humans who have ever existed, which is estimated to be around 117 billion, shows how quickly exponential growth gets out of hand. But thanks to pedigree collapse (repeated ancestors in family lines), the actual number of unique ancestors is much, much smaller—likely still in the millions for that many generations back.

It’s a fun reminder of just how interconnected we ALL are!