Indeed. The whole argument that captivity induces genetic drift, and
therefor bad, is a tautology. Of course there is genetic drift because
that's what happens when one population of a species is separated from
another. It might not have anything to do with captivity and just be the
process of natural evolution continuing along slightly different courses
in isolated populations. Sure, the conditions of captivity can influence
the evolutionary path, but that shouldn't matter much as long as the
animals remain able to survive in their natural environment. Without
constantly providing for genetic exchange between two populations held
in isolation, of course they're going to drift. Keep them separated long
enough and they may evolve into separate species. That's the way it works.
It seems to me that trying to keep a population of some threatened or
endangered creature genetically stable is as foolish as was the old way
that the National Park Service used to try and prevent any changes in
the forests. After a while the exclusion of fire and other disturbances
was destroying the very forests they thought they were protecting. I
don't think it would be helpful to actively prevent a species from
experiencing the genetic drift that might allow it to adapt and survive.
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