Creating a populace with sufficient genetic diversity

[smudboy]

This is not a question on the technical engineering feat to repopulate the world.

 

What I'm curious is this: what is the minimum number of people required to repopulate/create a healthy, genetically diverse community? That is, the offspring will not have negative characteristics that would otherwise compromise normal meiosis (abortion, retardation, mutations, etc.), and the community could thus genetically constitute itself, without any external people?

 

I recall hearing lots of silly debates about Adam and Eve, incest, a Slider's episode (a female world where men were in short suppy->sex farms) and a Star Trek episode (season 3, with Pulaski, they found a cloned world) stating the base number of humans required to get diversity up and running was something like 300.

 

Anyone know the numbers/sources?

[smudboy]

Well that's fascinating -- BobbyJoeCool just posted the same question...!

[LucidDreamer]

Considering that there is still a lot to be learned about genetics, I don't think an exact number can accurately calculated. The numbers required would be reduced if the members of the potential population were screened against disease causing alleles and for a healthy variation of traits.

[Mokele]

There's no one "magic number", and it depends a lot on species. A species with a lot of kids (assuming that you can keep all the kids safe and in captivity) will have a lot less genetic drift in the early stages of the repopulation than one that has only a few. That and inbreeding depression are the main problems.

 

You technically *can* repopulate from a small number, less than 100, but you're going to see some *major* screw-ups due to inbreeding, and it'd take many, many generations before mutations can restore even a semblance of proper genetic diversity.

 

Mokele

[jowrose]

cane and abel must have been pretty screwed up. no wonder cane killed him. or was it the other way around?

 

but really, that is a very interesting idea. Has anyone ever read "Invitation to the Game"? Same concept, where a group of people are sent to repopulate due to overcrowding. But I never considered the fact that genetically there would be a large number of mutations and the next few generations would be screwed up. Seeing as there were only a dozen people...

 

Another thing you might have to worry about would be the genetics becoming too stable and susceptible to a single disease. Like i read in popsci that the current banana population is at a huge risk to being wiped out because genetically they are all identical and a disease has been found that has started killing them in SE asia (i think). interesting article, by the way.