[meric]

For a genetic study of prevalence of a genetic condition in Chinese males, you'd want a homogenous group of Chinese males.

[cfelix]

I was referring about hiring people, not studying them. But I can't say you're wrong.

[meric]

If we really dig for an example - mountain climbing guides for Mount Everest, certain groups of people have evolutionary advantages that make them more suited for the job.

In an extreme environment where advantages of the tail end of population distributions are important then it's less likely the market will choose a diversified workforce.