Today’s question springs from a new study on a genetic mutation which causes a form of mental retardation among Amish.

Like other genetic research involving the Amish, this study will probably help them health-wise.  It’s really the language used to describe it which may not be quite so helpful.

In the article describing the work, researcher José Luis Rosa of the University of Barcelona states that “in these communities there are high rates of inbreeding, so homozygous recessive diseases are more frequent than in general population”.

“High rates of inbreeding” struck me, and I’m now predictably seeing the term pop up in other places to describe the Amish. To the non-scientific public, “inbreeding” is a stomach-churning word which in its worst sense suggests sexual relations between close (nuclear) family members.  Though criminal cases of abuse have occurred these types of relationships are not sanctioned by Amish.

There are at least two issues to touch on here: to what degree does, to use the researcher’s term, inbreeding exist among the Amish, and how it should be described.

Do Amish inbreed?

It’s true that it’s probably easier for the average Amish person to trace a genealogical connection to his spouse than it would be for a non-Amish person.  While close cousin marriages are widely discouraged, in a limited, largely closed population, more distant relations inevitably wed.  I have even heard Amish joke about this (“our family trees don’t fork”), but is this “inbreeding” as we commonly think of it?

It’s frequently noted that the Lancaster Amish population descends from a relative handful of immigrant families (see this explanation of genetic drift and the founder principle).  I would think that in the 18th century when there were only a few dozen families in the population, close marriages would have been more likely.

Today that should be a lot less of an issue.  Finding a spouse can still be problematic, particularly in small communities, as some newer settlements may be comprised by a majority of related families.  However this traditionally leads youth to seek life partners in other communities.

The answer to the question “Do Amish inbreed?” probably hinges on how you define the term, how close or distant a relationship must be to be considered “inbreeding”.  I’d argue the popular sense of the word suggests relations between very close family members, and so I’d say it’s not the best description.

What to call it?

As for the latter question, I’m no genetic researcher, but I’d have thought they might have chosen a less loaded and more clinical term like “endogamy“.  The person describing it seems to be Spanish, though the English of the sentence it is excerpted from seems excellent (however this may be a translation).  The article itself is online but behind a paywall; the abstract is readable here.

Perhaps the point in describing it this way was to make headlines for the study (such as this horror headline showing up in a major news outlet: “Amish Inbreeding Causes Genetic Mutation and Mental Retardation“).

Or perhaps what the Amish do can technically be described as inbreeding (and maybe this term is in fact commonly used in the genetic sciences). Unfortunately the word is so loaded that some people will glance at a headline like that and think Amish men marry their sisters.

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