User blog comment:Master Sima Yi/Assassinews 31-03-'15 — Assassin's Creed Chronicles announcement trailer/@comment-13471981-20150511182331/@comment-746824-20150511182953

Well, to be fair after a few generations of separation, genetic abnormalities from inbreeding and stuff like that no longer have mayor effects. Technically most people are descendants from a select few ancestors, I'm pretty sure.