[Houshalter]

No it's much closer to 1,000 years. Every generation the number of possible ancestors you have doubles. 2 parents, 4 grandparents, 8 great grandparents. Within a few generations back, you have literally millions of ancestors.

[bradleyjg]

Doesn't that assume no overlap? It seems like the odds of 2^n unique ancestors would be pretty low by the time you get to 10.

[maxerickson]

This seems like a reasonable discussion of the issue:

http://gcbias.org/2013/11/11/how-does-your-number-of-genetic...

After ~15 generations your genealogical ancestors aren't all that likely to have contributed much to your DNA.