What’s the minimum amount of people needed to repopulate the earth after an apocalypse? Please explain from a genetics POV how we know what is an acceptable size for the gene pool not to cause too many problems.

Question

Whenever I see a film that ends with it being up to a small group of survivors to repopulate the earth, I often find myself thinking that that group seems too small not to cause genetic problems within a few generations – too many cousins marrying each other and whatnot. You catch my drift hopefully.

In: Biology

Answer 1

Minimum viable population size. Franklin21 has proposed the famous 50/500 rule for minimum effective population size, which has become the threshold to prevent inbreeding depression22. This rule specifies that the genetic effective population size (Ne) should not be less than 50 in a short term and 500 in a long term.Mar 5, 2019
https://www.nature.com/articles/s41598-019-40340-z#:~:text=Minimum%20viable%20population%20size,500%20in%20a%20long%20term.

Less than 50 and its over it would seem.