Wednesday, May 16, 2012

Reflections on Inbreeding, Homophobia and Dixie

Robert Murphy makes an interesting observation about the newest leftist quip circulating about -- in case you hadn't heard it, the saying goes something to the effect that 'In North Carolina, you can marry your first cousin, just not your gay first cousin.'

Bob notes that the reason the joke is 'funny' rests on a bit of irony -- that it requires that one believe it eminently proper to hold a prejudice against one type of 'loving relationship,' while claiming it prejudicial and outrageous that the state should be interfering in another. It would seem more intellectually consistent to claim that people ought to be free to love whomever they like, supposing you're a proponent of the acceptance of gay marriage.

Well, we all know where this argument leads. I thought the most insightful remarks were along the lines that the 'hipsters' spreading this quip aren't attempting to be intellectually coherent but to simply take a cheap shot against bigoted redneck Southerners. It is ideological coherence which is the object here, supporting and mocking the right sets of people. But the part I found interesting was the attempted rationalizing against cousin marrying on the basis of 'science,' and the bizarre directions which the whole notion of 'consistency' on this topic would seem to take things.

I happen to know a thing or two about genetics, so I'll attempt to provide a bit of a crash course on some interesting points of population genetics. But be forewarned, I learned it some ten years ago and haven't done any of this since, so you'll have to forgive me if I don't get everything just exactly right.


There is actually only a fairly feeble scientific case to make against cousin marrying. In fact, cousin marrying is quite successful and common among various cultures, especially among what we would call Eastern. I won't go into the genetic 'benefits' of prolonged inbreeding -- suffice it to say that once a stable and healthy gene set has been established, it pays to keep them 'in the family' as this keeps out defective variants which the generations of inbreeding have removed -- but the actual observed risks are interesting, and not necessarily what one would expect. Franklin Roosevelt, former president of the United States, even, married one of his cousins, and Albert Einstein was the product of a cousin marriage, to no serious ill-effects so far as I know.

There are two genetic approaches to the calculation of the effects of inbreeding. The first is what the layman might expect -- the use of family trees and probability to determine the risk of 'homozygosity at a given locus by descent from a common ancestor,' which is a fancy way of saying 'the chance of getting two copies of the exact same gene because it was duplicated and passed along from the same person,' which is inbreeding defined genetically. This occurs because of 'circles' in the family tree, and is described mathematically in terms of 'inbreeding coefficients' or 'coefficients of relationship.' In the case of cousin marrying, the 'consanguinity,' or 'relatedness,' of this relationship is 0.125, or 1/8th, corresponding to a probability of about 0.0625, or 1/16th, that offspring from this marriage will display two identical copies of the same gene at any given locus because of inbreeding. Remember that number.

That kind of straightforward inbreeding can be thought of as a sort of 'short range' inbreeding. But there is another type which forms a sort of background inbreeding. This kind of inbreeding can be thought of as 'long range.' It arises out of a problem that should be familiar to fans of creation mythology.


Creation myths always runs into a problem with inbreeding. If Adam and Eve have kids, that's great, but what are their kids to 'do,' if not one another? Some myths introduce people from out of nowhere and neglect to mention where they came from. That is the case with the Christian myth. Others just go with it, and brothers and sisters and cousins and uncles hit it off and populate the world.

But it should be easy to see that introducing new people does not actually solve the problem, it just pushes it back a generation. If Adam and Eve's kids marry Jane and Steves's, well, who will their kids marry? Their cousins?

Any non-infinite population runs into this 'problem,' even if it isn't conscious of it, as ours mostly isn't. The inbreeding is still actually there, if very distant and undetectable with family trees.

You can also think about it in a sort of Darwinian way of thinking. If the generation of a new allele is a unique event (which probably isn't 100% true, but is a good approximation of things) any individual possessing two exact copies is evidence of inbreeding. So, all you blue-eyed people out there know how you got that way.

This effect is exacerbated by the existence of population substructure. Individuals typically do not actually pair up at random. There tend to be barriers -- geographic, social, cultural, etc. -- that create 'mating biases.'  By significantly limiting the pool of people which individuals of a group will tend to draw a mate from -- in a stable pattern that persists for many generations -- these behaviors tend to reduce the total 'genetic mixing' even below what could be achieved under the larger population size by breaking any large population down into smaller substructures. Even some intermingling will not be sufficient to produce a single statistical population, and these population subgroups will produce statistically measurable genetic effects over time due to their semi-isolation, even if they do not knowingly practice 'inbreeding.'

Statistics which look at the prevalence of homozygosity -- the condition of having two copies of the same gene -- versus heterozygosity can be used to detect these effects. If mating were truly random, one would expect a binomial distribution of the possible variations of genes at a given locus. This is called Hardy-Weinberg equilibrium. What one actually observes is almost always an excess of homozygotes and a deficit of heterozygotes. The degree of departure can be expressed with what are called F-statistics, which are comparable to the inbreeding coefficients discussed earlier, in that they also express 'the probability of homozygosity at a given locus by descent from a common ancestor,' just by a more roundabout method.

As it turns out, human beings depart considerably from the zero number that most people who consider a topic like this to be 'icky' would hope to see. But that is really only to be expected; if people were truly independently choosing mates, there could hardly be any racial minorities here for very long, and probably no local dialects, culture patterns, etc. They would disappear within a few generations. Most people marry someone of their own race, from their own geographic area, and from their own social standing.

Every culture is a little different, but most produce an F-statistic on the order of 0.10, which is more or less comparable to the 0.125 for cousin marriages. So, just by doing what they do in choosing a marriage partner, most people tend to pick other people who are about as related to them as their cousins, give or take about 25%. Actually, you also have to factor in the background F-statistic with the cousin marrying, so it would be a bit higher, but that's the ballpark idea. By the time you get to second cousins, the inbreeding thing is pretty much irrelevant.

I suppose some of you may need to take a vomit break.


This being a new idea to most people, it's interesting to take a moment and think about what it all means.

Firstly, most tend to take the whole mate selection thing fairly seriously. The idea of choosing a husband or wife totally at random -- or even more 'rationally,' from a totally different people group -- sounds absolutely insane, especially given what everybody knows about the difficulty of making marriage work. And yet, the notion of deliberate inbreeding is enough to send many people rushing to the bathroom. They would like to justify their behaviors and beliefs on the basis of 'science,' but science is here clearly telling them something that their common sense does not want to hear.

What this is is a clash of values.

I personally think it is easy to sort out. I think most people's common sense instinct is right, the important thing is for the marriage to work, 10% be damned. Whether the reader is willing to venture 12.5% is up to him. Anyway, I'm not changing my behavior or beliefs. The fact that I happened to marry a Chinese woman is simply a matter of chance. I thought she was the best, so I married her. End of story.

In different circumstances, the 'making it work factor' might take on even more importance. I mentioned before that other cultures actively encourage cousin marrying. The example of the Chinese is instructive, I think.

Imagine that you are a man living in a culture that is rather indifferent to the welfare of women on the whole, but that you in particular very much care for your daughters and sisters. Actually, you know that most men do, but like to put on a show of bluff and bluster, you know, to keep things in line. On the other hand, most people will tend to view other people's daughters and sisters rather coldly, especially if she has no male relatives around to defend her.

You know that once your daughters marry a man and leave your house, they'd be considered the property of the other family and cut off from your own, as lineage is traced through males only and you are no longer 'related' to a woman who has joined another family.

What would you do to help your daughters?

The Chinese solution was to 'keep them in the family.' You would try to marry them into your wife's family, especially to the sons of your wife's brothers, as you were holding their sister 'hostage,' so to speak. You implicitly held an axe over your brother-in-law's head, and the repeated 'swapping' of daughters between the two families also helped to solidify relations between them to keep their interests aligned.

As for your sons, you probably wouldn't care as much, since they were staying in your family and could look after themselves. But you would probably be receiving a constant stream of petitions from your sisters' husbands propositioning marriage of their daughters to your son, as your in-laws attempted to curry favor with you and place their daughters with a trusted family. You would probably be inclined to accept, as this gave you increased influence with your sister's family.

In this case, the uncertainty about the welfare of one's weaker members is a rather more intense concern than in our own culture. The values shift further in the direction of good placement, and the behavior shifts accordingly. This seems perfectly rational to me, and I have a difficult time condemning such 'inbreeding,' though I do think it would be a better solution for people simply to treat one another a bit more respectfully.

But one cannot control the behavior of others; he must play the hand he is dealt.


What about the issue of 'diversity?' This question poses some interesting head scratchers.

It might be suggested by left-leaning types that 'random mating' would be preferable, as it would appear on first glance to lead to 'more diversity.' Aside from the value questions posed above, and the value question posed by the notion of 'diversity,' well, would it?

That actually depends on what one means by 'diversity.' Changing mate selection patterns will have no effect on either the total number and variety of alleles,  (i.e., different kinds of genes) or even on their frequencies, assuming of course that there is no change in fertilities or other extraneous factors induced by this change. That is probably a bad assumption, but at any rate, if one is going to be discounting obviously more important values anyway, it is probably best to consider the effects in isolation. Anyway, this is hypothetical, and such effects (outside of a very likely rampant divorce rate) are not easily predictable.

The only thing that will really change in this hypothetical example will be the combinations of genes which are observed together. Basically, they will be thoroughly scrambled, until a Hardy-Weinberg equilibrium is established across all genetic loci. But whether or not this situation constitutes and increase of 'diversity' is still questionable.

For example, the fraction of people expected to show a skin tone as dark as an average black person I should think would decline dramatically, with a corresponding but probably less dramatic drop in the number with a skin tone as white as the average white. Blue eyes and blonde hair (except the artificial varieties) would disappear more or less completely, as would most characteristics which result from the possession of the homozygous recessive gene types.

Basically, dominant genes would have the run of the place, with the population moving towards a more or less 'average' appearance. This 'average' physique would span a somewhat broader distribution than the distributions presently observed for any particular racial group, but nothing close to the span observed between existing racial groups today. Thus, the not-so-unique more 'extreme' characteristics of today would become exceedingly rare, as the probability of the necessary genes coming together would greatly diminish, and human tendencies being what they are, such individuals who would today only be called normal members of various racial groups would probably be in for at least a bit of treatment as a genetic 'freak.'

I suppose this could be considered an increase of diversity from a certain point of view, but most people would consider it to be the opposite -- the destruction of diversity. It would seem to me that the behavior that produced more of what people would recognize as 'diversity' would be attempts at actually increasing genetic barriers in order to 'preserve' the races as they are, and maybe even create some new ones. Probably the best tools to accomplish that would be new 'social codes' to encourage social segregation.

But that really isn't a very progressive idea.


Indeed, if one were to assess the degree to which 'inbreeding' is actually occurring, I would suggest that the South would probably not score very highly. It might beat out, say, the West Coast, but if I were a betting man, and could send Sewall Wright (apparently yet another genius who is the product of a cousin marriage) out to measure America's inbreeding statistics, I suggest that the places he would find the most would probably skew to the political left and would be located in the Northeast.

The reason I say this is that I simply don't see too much of the kinds of attitudes in the South that would lead to strongly selective mating patterns as I see in the Northeast, though I suppose that that, too, could be construed as an insult by the kinds of people who came up with the first inbreeding-homophobia salvo. But then, I suppose they aren't exactly concerned with intellectual rigor, anyway.

Certainly, there are social divisions here, but over the course of time I have learned that they pale in comparison to the divisions which exist in the North. Which I'm not saying is bad, but nevertheless appears to be fact.

Gene Callahan linked to an interesting/revealing map compiled with census data that showed (or at least claimed to show) the primary 'ancestry' of the populations of each county in the US. 'Ancestry' being, for example, Italian, German, African, etc. What was 'revealed' was that huge swaths of the South claimed their 'ancestry' as 'American.'

Northerners often don't know this, but in the South we don't give two flips about this European descent stuff, and it actually makes some people angry, which is what that map really says. It also reveals the level of insularity and social detachment of the eggheads at the Census Bureau not to know that something like that would happen if they asked such a stupid question. It would be as if bureaucrats in Alabama had made the questionnaire instead, and included a question about the man-of-the-house's preferred caliber of handgun, then were surprised when they got nonsensical responses from 'large swaths' of the coastal and Great Lakes regions. What appears 'relevant' information depends very much on who is asking the questions.

In the South prevails a much more practical attitude toward the matter of race than in the North, if far less sophisticated. Basically, there is a sort of two-track categorization of things. The first is more biological, and the second more social.

Southerners mostly bother to recognize no more than about four races -- 'white,' 'black,' 'Mexican,' and 'Asian/Other.' It is not that they do not know of the finer gradations, it is only that they are not really obsessed with the topic and do not have (or want) time and attention for it. This is all that they will spare, and that often grudgingly. The best approach for a non-Southerner unused to such coarse categorization is to accept your category and go with it. After all, it will pretty much not come up and be of little to no significance anyway. But if you choose to make yourself annoying by pressing the issue, you will find yourself re-categorized at the social level of categorization, which is the more important level, and far more differentiated.

If for example, if you decide that it is very important to be recognized as Irish/Italian and not just 'white' because it is a critical component of your identity, you will be summarily reclassified as 'not white' socially. More specifically, despite whatever protestations you make, you will be categorized as 'annoying Yankee twit,' which falls in the second main social category of 'troublemakers who piss me off.' It will be very difficult to get yourself uncategorized out of this particular bin. I would suggest moving.

In the social category, the broadest two categories are 'white,' and the 'troublemaker' category. But here, 'white' does not mean racially 'white.' It means 'I want to be a part of mainstream society and basically get along with others, not foment divisiveness.' I call it 'white' only because it refers to the historically dominant culture, which is descended from biologically 'white' culture, and that is basically how people think about it, even though actual race has little to do with it. It is, after all, a social categorization, and not a biological one.

At the social level, anybody can become 'white,' even if he is not biologically 'white.' 'Race,' again, whatever that means under this odd system, does not much matter beyond the biological. Other 'white' people are almost all perfectly willing to accept anyone who wants to be 'white,' even if neither the 'acceptor' nor the 'acceptee' are actually 'white' in the biological sense. 'White' people in general actively want others to join them, and I would say that, in general, most people of the South belong in this category, despite what one hears about the volumes of illegal immigration and whatnot. But, in general, if you insist on being a troublemaker, there will be no trouble about tossing you into the other categories and about you suffering the social consequences for your rejection of social norms.

But -- to return to the question of inbreeding.  There are some Southerners who treat their lineages as something of a hobby, I will admit, but this is far less a matter of their identities than I have observed among Northerners. Most people have only a vague idea of their ancestry. Within the 'white' biological category, it poses essentially nothing of a barrier as far as mate choice is concerned.  It might as well not exist.

The biological categories do pose a moderate barrier, but not as much as one would guess. In the South, the 'races' tend to exist in much closer associations with one another and tend to treat the situation more practically rather than intellectually, as the attitudes I have just described would suggest. Kids, being kids, tend to 'fall in love' rather indiscriminately with the people around them, and since almost all attend unsegregated public schools through these years, there tends to be a fair amount of crossing over between categories. Private schools and universities attract a far smaller share of students, and even so, tend to reflect the broader public attitudes in their makeup.

The social categorization appears to matter most. Parents and families, especially of the 'white' social categorization, do not want their young ones marrying 'troublemakers.' Wealth also tends to matter, as might be expected. But both of these categorizations tend to be rather volatile, so I would doubt that the ways in which they skew things would be expected to prevail in a systematic fashion over the long run as far as genetics are concerned.

Mostly, it boils down to a very basic scenario such that in the struggle to find someone 'like me,' the rather broader notions of 'like me' that tend to prevail in the South would suggest that population substructure and genetic barriers are lower here than in a place like the Northeast, where such identities seem to be much stronger. We have, for example, neighborhoods differentially populated with individuals corresponding to the broad racial categorizations I have described, but absolutely nothing approaching the ethnic individuation one might find in the boroughs of New York City. I would therefore expect the North to show somewhat higher inbreeding coefficients in the form of f-statistics.

I guess that's what 'sophistication' gets you, supposing that one cares about these kinds of things. But anyway, I'm not judging, just reporting the facts and speculating a bit about them.


As to the homophobia, it falls as might be expected into the social category of things. Most people understand that a person is not necessarily in much control of his impulses. Some pine after booze, some bite their nails. Some really peculiar people find Kim Kardashian to be interesting.

The important thing is not so much the impulse, but what one does with it. Troublemakers are those people who allow their impulses to screw up their lives and cause aggravation and trouble for others.

So, if you have the homosexual impulse, but you are respectful and responsible in your conduct, which means not inflicting yourself on people in ways which they find to be aggravating, you'll probably do okay, even in the South. A Southerner's idea of what is 'aggravating' may be different from what you are used to or think ought to be the case, but really, that isn't for you to decide. You're here, not someplace else; fair is fair. Don't stir up trouble, and you can still be 'white,' if you want to. Hang around long enough, and maybe we'll listen to you. But my bet is we'll be making the dent in you, and not the other way around.

The same goes for alcoholics, nail-biters, and, yes, even Northerners. Pretty much everyone.

But probably not for Kim Kardashian. I don't think that's possible. It's a fairly evenhanded system, but there has to be some sanity.

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