[Helio Centric]

Helio Centric asked the Naked Scientists:
   Chris,

I was recently reading about more 'undiscovered' tribes being found in the Amazon. This set me thinking about the minimum population size such an isolated community would need to be in order to maintain a healthy genetic diversity over such a long time period as we are all familiar with the issues of inbreeding that can create undesirable genetic outcomes. how do these isolated communities do it?

Regards,

Helio Centric
What do you think?

[RD]

When inbreeding effects are included, estimates of MVP for many species are in the 1,000s. Based on a meta-analysis of reported values in the literature for many species, Traill et al. reported a median MVP of 4,169 individuals.

http://en.wikipedia.org/wiki/Minimum_viable_population

The "undiscovered" tribes don't remain healthy after being contacted ...

A major problem with contacting isolated people is that they will lack any immunity to common diseases, which can be devastating to a closely-contained population with no natural immunity

http://en.wikipedia.org/wiki/Uncontacted_peoples

I suspect the tribes are not truly isolated : they will occasionally gain members (new blood) from other such tribes,
 ( not necessarily voluntary ... http://en.wikipedia.org/wiki/Bride_kidnapping )