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.

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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

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Anonymous 0 Comments

Well, to judge by past experience,

> A 2005 study from Rutgers University theorized that the pre-1492 native populations of the Americas are the descendants of only 70 individuals who crossed the land bridge between Asia and North America.[9]

There would have been others, who have no living descendants. And of course, that doesn’t mean they didn’t have inbreeding problems.

> In 2000, a Molecular Biology and Evolution paper suggested a transplanting model or a ‘long bottleneck’ to account for the limited genetic variation, rather than a catastrophic environmental change.[8] This would be consistent with suggestions that in sub-Saharan Africa numbers could have dropped at times as low as 2,000, for perhaps as long as 100,000 years, before numbers began to expand again in the Late Stone Age.[15]

https://en.wikipedia.org/wiki/Population_bottleneck

See also “Minimum viable population”

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