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

Some cultural practices promote this (eg some Arabic groups preference cross-cousin marriage). But humans don’t live in isolated groups. Foragers live in bands which meet regularly, and usually have rules about who you can marry (some West Australian groups have rules so complex that anthropologists needed algebra to map them). One purpose of the meets is to negotiate marriages. The minimum number needed to keep a language alive (language being the marker of who’s in ‘my tribe’) is around one thousand, which is more than enough to avoid the accumulation of genetic risks and probably the minimum number in regular contact (not all at once- but gatherings of 50-100 once or twice a year, each gathering connecting to another)