genes vs. genes

on the one hand we’ve got the westermarck effect, presumably coded for by some gene/s that have been selected for ’cause too much close inbreeding is maybe not a good idea. at the very least, it kinda defeats the purpose of sex (whatever that might be — apart from fun, that is).

on the other hand, we’ve got genetic sexual attraction, presumably coded for by some other gene/s that have been selected for ’cause, well, genes just “wanna” reproduce themselves, and if you mate with someone like yourself you wind up with little ‘uns who have LOTS of those genes.

sounds like an example of intragenomic conflict to me.

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boinking your sister

heh. several of you were grossed out at the thought — and that’s good! that is as it should be.

i don’t have a brother, so i don’t know what the westermarck effect feels like, but apparently it feels like … ewwwwwwww! and it doesn’t just work for sibilings, but any kids that are raised together. i’ve read many accounts of muslim couples who have been made to marry their first-cousins who complain that they’re not attracted to each other and very often they were raised together (in an extended family household), so they feel like … ewwwwwwww!

robin fox had a lot of interesting stuff to say about the westermarck effect in “The Tribal Imagination” (chapter 6 — and also presumbaly in his book on incest, but i haven’t read that). here’s an excerpt for ya [pgs. 128-31]:

“Taboos on sexual relationship between close kin, between the members of the immediate family, were long thought to be a purely human invention. Animals, it was maintained, had no such inhibitions and mated incestuously. Thus the taboos on such animalistic behavior were thought to be the very foundation of human society; they were the ultimate Drumbeat of humanity, by which, in the immortal words of Levi-Strauss, culture said ‘No!’ to nature….

“The move from nature to culture represented by the imposition of the taboos was seen as precarious and counter to natural motives, which were ineradicable. In consequence, the taboos had to be stern and enforced by constant vigilance. In this traditional view, we all wanted to make love to our nearest kin, but once the momentous leap into culture had been taken, it would have been disastrous to go back into the maelstrom of incestuous animality. Our societies were built on the presumption of mating outside the family, it was the very definition of humanity itself, and so stern taboos, laws, and punishments were needed to keep incest at bay.

“This was a plausible view because societies did almost universally ban sex and marriage within the immediate family, and punishments for breaches of this rule were often severe, including torture and death. In their mythologies, primitive tribes and ancients societies often portrayed incest, and the results of it were usually disastrous. There were exceptions to the rule (and we shall return to these), but they were almost always royal exceptions, and royal persons, as gods on earth, were allowed behavior that was not allowed to ordinary mortals. On the whole, then it was agreed, there was a ‘grisly horror’ of incest (Freud) that universally afflicted people and led them to impose and enforce the taboos, often extending them beyond the family to members of the clan, variously defined. Why, the question went, would we have such strong taboos if we did not have the strong desire in the first place?

“Both popular opinion and the collective voice of the behavioral sciences echoed this orthodoxy. But there was always an undercurrent of skepticism. Why, the objectors asked in turn, do we seem, by and large, not to want to have sex with our closest relations? This would be the common-sense observation. Incest happens, but in proportion to non-incest, it does not happen very often. And most of this avoidance of incest does not seem to result from fear of punishment; there seems to be a genuine aversion to incest. This aversion seems to vary according to the relationship: strongest between mother and son, weakest between father and daughter, variable between brother and sister. But it is there, and usually only breaks down in unappetizing circumstances.

“The orthodox view said that left to our own devices we would immediately resort to incest and so we have to be reined in by strong taboos and sanctions…. The skeptical view says that, on the contrary, left to our own devices we would probably mostly avoid incest spontaneously. The orthodox view asks why, then, if this is so, are there the universal strong taboos?

“The skeptic answers that we often taboo the things that we are averse to, not because we secretly want to do them, but because we disapprove of people doing things that are generally obnoxious to us. We strongly taboo murder, not because we are all given to implacable murderous impulses, but because we are averse to it, so that even if only a few people do it, it offends us. We do, however, understand the temptation to do it; we have all perhaps felt it momentarily. So the subject fascinates us and permeates our legends and stories from the beginning. Sex and violence, incest and murder — often linked in our fantasy productions — persist in our imaginative attempts to interpret ourselves to ourselves….

“[I]n looking at animal behavior under natural conditions, indeed at the behavior of all sexually reproducing organisms, outbreeding seemed to be the rule and incest was rare. This was especially true in our primate relatives, and so by implication in our ancestors during the long haul through the savannas and the ice….

“The origin of this sexual reproduction is still a mystery, but whatever the reason, this new form of reproduction won out over its rival (which is still around) by virtue of its ability to produce instant genetic variability for natural selection to work on. Close inbreeding results in a loss of such variability, hence mechanisms evolved to avoid it. At the same time, if inbreeding becomes too random, then any beneficial genes will be dissipated rather than concentrated and preserved. It is this loss of variation that seems to be at the heart of sexual strategies, not the bad genetic effects of close inbreeding. In small bands these effects would quickly be bred out, and even scattered bouts of outbreeding would reestablish a healthy stock.

“So nature aims for a middle ground: organisms breed out to avoid losing variability, but not so far out that they dissipate genetic advantages. In human terms this means that the immediate family is taboo, but that marriage with cousins should be preferred. This is exactly what we find in human history until the dramatic growth and disruption of human populations upset the natural balance of the traditional society.”

actually, this is exactly what we find in human history until the roman catholic church started fiddling with mating patterns in europe in the early middle ages (see Inbreeding in Europe series down below ↓ in left-hand column).

“[I]f inbreeding becomes too random, then any beneficial genes will be dissipated rather than concentrated and preserved.”

think about that in terms of altruism genes.

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sperm donation and possible inbreeding – oops!

from the nyt (ghengis khan, move over!):

“One Sperm Donor, 150 Offspring”

“Cynthia Daily and her partner used a sperm donor to conceive a baby seven years ago, and they hoped that one day their son would get to know some of his half siblings — an extended family of sorts for modern times.

“So Ms. Daily searched a Web-based registry for other children fathered by the same donor and helped to create an online group to track them. Over the years, she watched the number of children in her son’s group grow.

“And grow.

“Today there are 150 children, all conceived with sperm from one donor, in this group of half siblings, and more are on the way. ‘It’s wild when we see them all together — they all look alike,’ said Ms. Daily, 48, a social worker in the Washington area who sometimes vacations with other families in her son’s group.

“As more women choose to have babies on their own, and the number of children born through artificial insemination increases, outsize groups of donor siblings are starting to appear. While Ms. Daily’s group is among the largest, many others comprising 50 or more half siblings are cropping up on Web sites and in chat groups, where sperm donors are tagged with unique identifying numbers.

“Now, there is growing concern among parents, donors and medical experts about potential negative consequences of having so many children fathered by the same donors, including the possibility that genes for rare diseases could be spread more widely through the population. Some experts are even calling attention to the increased odds of accidental incest between half sisters and half brothers, who often live close to one another.

oops! i wonder what the odds are for such accidental incest between half-siblings living in the same area? the calculation shouldn’t just be a numerical one (x number of half-siblings divided by the total population, or however the h*ck you’d do the math). no, you’d also need to factor in the fact that siblings would more likely be drawn to similar interests and, therefore, might be even more likely to meet: they both might wind up in the same discipline at the same local university or both wind up taking guitar lessons or whatever.

and when they do meet, there are good chances that they’d be — as they’d prolly experience it — inexplicably attracted to each other in the strongest possible way:

“Fast-forward then to 20 years later when another young man and woman, this time James and Maura [half-siblings that never knew each other], meet in eerily similar circumstances.

“Both of them happen to be out socialising with friends in a town which neither of them is from. They are instantly smitten. So strong is their incredible mutual attraction for one another, that a week later both of them feel they have known each other for a lifetime.

that’s because they share a great number of genes with one another.

normally, when children are raised together (and they have to actually have physical contact with one another as children, i.e. play together) between the ages of 0-6, a kind of imprinting happens which typically makes them NOT sexually attracted to each other when they grow up — i.e. the westermarck effect. siblings or half-siblings raised apart miss out on this imprinting, so if they meet each other as adults, they often experience this “incredible mutal attraction.”

the couple in the story above, james and maura, actually married and have had a couple of kids together. i don’t think this is a problem. even though we have a taboo against siblings mating, it’s really not morally despicable for siblings to mate if you think about it. as a society, we wouldn’t want it to happen all of the time on a regular basis — too much inbreeding, not good. but occasionally? i’ll give ’em a pass — especially in these accidental cases.

i would recommend such a couple to have some genetic screening done first, tho, before having kids, just to be safe. half-siblings are, obviously, not as related to one another as full-siblings; but, rather, to the same degree as an uncle-niece/aunt-nephew. iow, more than first-cousins. (the same as double first-cousins, tho, which is a common form of cousin marriage in places like saudi arabia.)

the question remains, however, what does all this sperm donation mean for our society? what does it mean when one man fathers 150+ children? well, it’s really just a form of polygamy in a way, isn’t it? or, at least, it kinda-sorta has a similar side-effect — a greater number of individuals who are related to one another as half-siblings.

what if this were done on a huge scale? what would the effects be? i’m not sure. if you did it repeatedly over many generations, i guess you’d eventually wind up with some sort of clannish or tribal society. maybe more clannish than tribal (you’d need some focused inbreeding for that, i think) — but only if everybody stayed put in the areas in which they were raised.

if you — and this is obviously only an extremely hypothetical situation that would never happen in reality — if you made sure to move everybody, or maybe half the population, around every generation, shuffled them up, i guess you’d get a more cohesive society than we have today, for instance, because everybody would be more related, but we’d avoid the effects of clannishness from too much local inbreeding. you would’ve narrowed the gene pool by making almost everyone in society the descendants of, say, 1M men as opposed to 87M men. what you’d do with the 86M men who didn’t get to breed?…i dunno.

oh! i guess you could just arrange it so that all women had to have one child via a sperm donor but the rest she could have with her husband! that would narrow the gene pool, too. man, my skills are wasted. i’d be GREAT at this cultural revolution stuff! (those are all copies of “the selfish gene” that my followers are displaying.) (~_^)

if the idea that too much outbreeding has lead to too loose genetic ties in the west and, consequently, to the fragmentation of the west is correct — maybe more sperm donation (or polygamy) for a while is just what the doctor ordered! you wouldn’t want to do it forever, tho, ’cause then you’d just be left with some messed up tribal society or something.

(note: comments do not require an email. every sperm is sacred!)