if procreating with close relatives causes dangerous mutations and increased risks of disease, how did isolated groups of humans deal with it?

Question

if procreating with close relatives causes dangerous mutations and increased risks of disease, how did isolated groups of humans deal with it?

In: 562

Answer 1

Just because in has increased risks doesn’t mean it won’t work. If you went from a 5% chance of having a child with serious defects to a 50% chance of having a child with serious defects, you still have a 50% chance of bearing a child who doesn’t have serious defects. If a small group of isolated people gets lucky, they can still survive and prosper. Some isolated groups of humans died out, and some managed to survive.