re: Interesting article on poverty in Appalachia

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Unfortunately you should. It happens. Had a 6 year old in a facility I worked in a few years back that was a direct result of Eastern Kentucky incest. And had developmental issues as a result.

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The problem is less first degree relative coitus than the fact that these families have been in the same area for generations with no new blood coming in. You'll find the Smiths, Joneses, Jacksons, Walters, all marrying then stop for a generation or two and the families they married out to doing the same but eventually those families marry again because they're not family anymore but they don't realize they share genes due to small population size. After a while these families start to share genes that would be diluted in other places due to population. However, the relatedness of so many families swapping genes in a relatively small population makes certain bad genes more likely to occur because several families are now carrying that gene even if they're no longer related enough to matter legally, culturally, or medically (if they were in another place with a larger population group that is).

However first degree incest has never been any different in the mountains than elsewhere -- not even in the old days. The same issues arise in European royalty (a few families who are all related to one another via various marriages and who've all married in to different royal families at different times but who aren't related enough anymore to where it should matter). The trouble is some genes require doubles and you increase the likelihood if there's a long history of marriage between a smaller genetic pool despite not being related enough to count. Even so, it's still quite rare for even the worst cases of of repeated 1st degree relative consanguinity to produce serious defects. It happens but mostly among populations known to carry specific genes that can cause defects.