I had to look up "heritably"; it means ability to pass genes from one generation to the next.

I had a similar thought regarding a recent post on the Orvis blog about Greenback Cutthroat trout. Apparently, the only true genetic strain was confined to a single stream containing about 700 individuals. Now that population is being used to repopulate parts of the original range. Talk about lack of genetic diversity! Especially when you realize Greenbacks are just an isolated strain of the broader cutthroat group, which is probably just an offshoot of the Rainbow group.

Regarding people, the best way to preserve gene pool diversity is for different races to intermarry. The worst thing would be to marry someone who looks like you and comes from a similar region of the world. But that's exactly what people tend to do.

Anyway, interesting thoughts, Larry.