Ok, I can understand why their would be an increased risk of recessive genetic diseases as a result of inbreeding, but why the increased likelihood of slower growth rate, shorter adult height, and asymmetrical faces? Are “slow growth” and “shortness” generally recessive qualities? Why the increased incidence of asymmetrical faces? I find that the most puzzling. Anyone have a link to case-study type photos of “typical” inbred?. Guess that’s a lot to ask for.
This might be considered typical if you continually breed within a single Zip Code.
This family is certainly and interesting case study in inbreeding.
There was an interesting study a couple of years ago that did 2-d Fourier analysis of faces in photographs. The “best looking” faces generally had the smoothest distribution of waveforms.
[my WAG] It would seem likely that the effect on faces due to inbreeding is that certain “frequencies” would be overrepresented and others underrepresented. I.e., they would be “not so good looking” and certain near-extremes in shapes would be noticable. E.g., the famous Hapsburg droopy lower lip.[/my WAG]
Note that what distribution of traits get strengthened due to inbreeding is largely determined by what was there in the original pool. You could end up with people that are generally short, generally medium, or generally tall. All based on the luck of the initial DNA set and subsequent losses.
Since you brought it up in your title, was the banjo player in ‘Deliverance’ inbred, have some genetic ‘syndrome’ or just a funny looking guy?
Billy Redden is just an odd looking guy. He has a cameo in Tim Burton’s Big Fish. More about Billy.
A tangential inbred twins question:
I remember a photo from a couple of years ago of two brothers. Suffice it to say that they had a very distinctive appearance, both having prominent ears and very high, almost conical heads. It is possible that they were South African (???), and that they were taken by a photojournalist researching isolated rural communities.
Can anyone track down the photo or details thereof?
This sort of sounds like microencephaly; sufferers are more commonly known in circus sideshow lingo as “pinheads.” They were often billed as “Wild Men of Borneo” (Zippy the Pinhead) or “The Missing Link” or some other sensational story of someone born in a less exotic locale, like the Bronx. Here is a photo of two brothers, just scroll down the page (Warning: disturbing pictures of sideshow freaks):
I don’t think those are two brothers pictured in your link, KidCharlemagne. I think they are Elvira and Jenny Snow, twin sisters from Georgia. And yeah, I think the condition SentientMeat describes sounds like an extreme case of microcephaly.
Some cases of microcephaly are caused by a recessive gene. The chances of a child being born with microcephaly are higher if both parents carry this recessive gene. Thus, an incestuous couple has a greater chance of having a child with microcephaly if and only if the gene runs in their family.
I recognise that from your description. We had that picture on our company noticeboard until very recently (with two coworkers’ names on it, of course). They’re wearing dungarees and drooling IIRC - is that right? I thought they’re twin brothers from an isolated rural community in Russia (or the Ukraine?).
I can’t remember what they were wearing (shirts and jeans?) and I’m sure they weren’t actually drooling, but they did look rather backward; I’m sure it must be the same pair.
Try it out on the NADS crowd perhaps?
So who’s Hoyt Pollard? I remember reading that was the banjo kid.
OK, this Pollard is listed in the Deliverance film credits as ‘boy at gas station’, so I guess people just assumed it was the banjo kid. But Billy Redden is also listed there as ‘Lonny’…Pollard was probably just another character.
I’m not sure any of the traits you cite above are bona fide indicators of inbreeding. There was a study that made the cover of Science years ago where the investigators morphed a bunch of female faces of widely varying ethnicity, which were deemed beautiful from the get-go, to produce a digital chimera that was judged on average to be more beutiful than any of the faces from which it was derived. From this the authors claimed that “average is beautiful”, meaning genetic diversity is reflected in the face, and we are endowed with the ability to recognize sufficiently mongrel faces and prefer them to those of less diverse heritage. One of the things we associate with beauty is facial symmetry, so it follows facial symmetry is an indicator of genetic diversity.
But this hypothesis (and that’s all it is), doesn’t always hold up to close scrutiny. It’s generally agreed that beauty is uncommon, and that “average” can be improved upon. Siblings can be more or less “beautiful”, yet have the same genetic diversity, or lack thereof. And it’s been proven in many species (including primates) that left on their own, animals typically pick second-cousins to mate with. This would seem to fly in the face of the hypothesis of genetic diversity determining mate preference, and indicates that diversity is good to a point; but sometimes keeping it in the family is a good way to hold onto and magnify desirable traits, so a certain amount of consanguinuity above what would be expected of true panmixus tends to exist. “Beauty” certainly does probably indicate something desirable about the individual from a mating standpoint, but you might be surprised to find that kissin’ cousins are the real hotties.
As for average height and growth rate, look around the world: In Africa, for instance, you can find real short folks in the Congo valley (e.g. Pygmy), and then fly a few hundred miles away to the Serengeti and find enthic groups who average over six feet (e.g. Masai). Both kinds are composed of people who are probably much more “inbred” than a typical central European, who’s height would probably fall in between. Selective pressure on height and body mass is the determining factor in size (and I would extrapolate, rate of growth), and it seems to me that you could inbreed tall people and short people and they would remain, on average and respectively, tall and short, since they inherited those traits from their parents.
I can’t comment on the reliability of this source other than it’s a .edu. :