year-end summary, 2011

i tried to come up with a top-ten list of what i think were my most important (delusions of grandeur!) posts this past year, but instead i’ve got a top-seventeen list. sorry, i just couldn’t whittle it down any further. (^_^)

if you’re new-ish to the blog, it might be useful to read these in order if you want to catch up on the conversation. if your new year’s resolution is to read only one blog post per day, and it’s after midnight where you are, then i recommend four things from last month:

jan: reductionism works
feb: cousin marriage conundrum addendum
apr: whatever happened to european tribes?
may: father’s brother’s daughter marriage
jun: genes for altruism
jul: medieval manoralism and genetic relatedness and and so my next question naturally is…
aug: setting the stage? and “hard-won democracy”
sep: but what about the english?
oct: technical stuff
nov: mating patterns and the individual and which altrusim genes? and inclusive inclusive fitness and four things
dec: the middle ages and visions of altruism genes

happy new year everybody! (^_^)

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sociality genes

ruh roh:

“Genes Play Major Role in Primate Social Behavior, Study Finds”

“Social behavior among primates — including humans — has a substantial genetic basis, a team of scientists has concluded from a new survey of social structure across the primate family tree.

“The scientists, at the University of Oxford in England, looked at the evolutionary family tree of 217 primate species whose social organization is known….

“[T]he new survey emphasizes the major role of genetics in shaping sociality. Being rooted in genetics, social structure is hard to change, and a species has to operate with whatever social structure it inherits.

“If social behavior were mostly shaped by ecology, then related species living in different environments should display a variety of social structures. But the Oxford biologists — Susanne Shultz, Christopher Opie and Quentin Atkinson — found the opposite was true: Primate species tended to have the same social structure as their close relatives, regardless of how and where they live….

The Oxford survey confirms that the structure of human society, too, is likely to have a genetic basis, since humans are in the primate family, said Bernard Chapais, an expert on human social evolution at the University of Montreal.

“‘Evolutionary change in any particular lineage is highly constrained by the lineage’s phylogenetic history,’ Dr. Chapais said, referring to the evolutionary family tree. ‘This reasoning applies to all species, including ours.'”

oh my lord! pass me the smelling salts — i do declare, i think i’m gonna faint!

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visions of altruism genes

i had visions of this schematic diagram (along with sugarplums, of course!) knocking around in my head over christmas. for those of you who haven’t been following along, it came to mind ’cause of a brief conversation in this comments thread here.

the slopes might not be exactly right for conveying what i’ve got in mind — if i had actually drawn the graph myself, maybe they’d be more “right” (i brazenly stole and adapted the graph from wikipedia) — but hopefully you’ll get my general meaning. see what you think:

(hint: as the degree of inbreeding in a population increases, the number of reciprocal altruism genes decreases while the number of “sib-altruism” genes increases. and vice versa.)

previously: technical stuff

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the middle ages

working hypothesis: that the medieval period was a d*mned interesting time wrt selection pressures on europeans (and by europeans i mostly mean northern europeans, altho interesting stuff undoubtedly happened in the south, too) and a lot of the genes for the characteristics we associate with h. europaeus were selected for during this time period.

i know — it’s a long time period, but that doesn’t make it any the less interesting or remarkable.

you’ve got:

– the ashkenazi jewish iq thing [opens pdf], a la cochran, laurel and hardy, and harpending. (you might quibble that they’re not really europeans — ashkenazi jews, that is, not cochran, et. al. my point is, tho, that their high average iq — the ashkenazis, that is — seems to have been selected for in medieval europe.)

– the middle class traits and general independent spirit of the english (and possibly other northern europeans) prolly being selected for starting in the medieval period.

– the shift from tribes to not-tribes via the changing mating patterns which prolly impacted altruism genes amongst other behavioral traits.

– manoralism. not sure what traits might’ve been selected for due to the manoralism system in europe. for one thing, the manors, along with the church, contributed to the, relatively speaking, genetic unrelatedness within some european populations. that the manor system never really took hold in places like greece and italy (according to mitterauer) might explain a lot about those populations. also, i’m guessing that manoralism — which wasn’t very powerful in england either (feudalism arrived quite late there, no?) — might’ve select for somewhat docile personalities. you know — individuals who will go along with what the masser (whether that be the monastery or the lord of the manor) or the group has to say rather than being fiercely independent? conformists, in other words. think: germans.

– the ostseidlung. the eastward expansion of germans (and others) in many cases within the manor system again. selective pressures?: for hard, efficient workers. again, not too uppity. high-ish iq?

– meanwhile, southern spain and italy had arab/north africa settlement and rule for a time. ireland and other “celtic fringe” areas ignored the church regulations on marriage and didn’t really adopt the manor system, either. eastern europe? who knows? (somebody other than me!)

– the black death.

new year’s resolution for 2012 (is it too early to make resolutions?): think and learn more about the selective pressures on european populations during the middle ages.

previously: and so my next question naturally is… and setting the stage

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too much altruism?

clearly there can be/are probably many different types of altruism genes present in varying frequencies in different human populations — possibly some are not even found at all in some populations.

“genes for altruism” are obviously a good thing, at least in some circumstances, otherwise they wouldn’t be around. but it is possible to have too much of a good thing. (except for chocolate.)

it seems that too many “sib altruism” genes in high concentrations means that you wind up with clannish or tribal societies, which might be great in some places and at some times, but they tend to hinder the development of a modern, liberal, democratic society — if that is your aim.

otoh, perhaps too few “sib altruism” genes means your society weakens too much at the seams and starts to unravel. perhaps too many “genes for reciprocal altruism” can get your society in trouble, especially if it comes up against strong tribalistic societies.

a while back, john quoted this passage from bill hamilton:

“The incursions of barbaric pastoralists seem to do civilizations less harm in the long run than one might expect. Indeed, two dark ages and renaissances in Europe suggest a recurring pattern in which a renaissance follows an incursion by about 800 years. It may even be suggested that certain genes or traditions of pastoralists revitalize the conquered people with an ingredient of progress which tends to die out in a large panmictic population for the reasons already discussed. I have in mind altruism itself, or the part of the altruism which is perhaps better described as self-sacrificial daring. By the time of the renaissance it may be that the mixing of genes and cultures (or of cultures alone if these are the only vehicles, which I doubt) has continued long enough to bring the old mercantile thoughtfulness and the infused daring into conjunction in a few individuals who then find courage for all kinds of inventive innovation against the resistance of established thought and practice. Often, however, the cost in fitness of such altruism and sublimated pugnacity to the individuals concerned is by no means metaphorical, and the benefits to fitness, such as they are, go to a mass of individuals whose genetic correlation with the innovator must be slight indeed. Thus civilization probably slowly reduces its altruism of all kinds, including the kinds needed for cultural creativity (see also Eshel 1972).”

like pretty much every paragraph written by hamilton, there are at least five original ideas here and about ten really interesting side notes. (~_^)

one thing: hamilton suggests that the occasional invasion by tribal barbarians may be a good thing for civilizations since they prolly introduce some fresh altruism genes into aged societies in which the altruism genes have been watered down too much. that’s probably correct (i can’t see why it wouldn’t be); however, i have been thinking for some time now that a society with watered down altruism genes ought to be able to get back to a more altruistic state simply by stepping up its internal inbreeding a bit. i think that should work, provided there are enough altruism genes left in the population and they haven’t (almost) all been deselected (if that’s the right way of putting it).

problem is, this is not a quick fix. it might take a few generations to get your society back to where you want it to be. and, of course, with too much close inbreeding you run the risk of developing high concentrations of “sib altruism” genes in certain lineages, yada, yada, yada. so you’ve got to know how to inbreed AND when to stop. (don’t ask me what the ideals are!)

also, since it’s quite possible/likely that different populations may have different altruism genes, it’s not certain that any given failing civilization would necessarily want the altruism genes of whatever barbarian group happened to turn up on its doorstep. the barbarians might bring some good altruism genes (just what the doctor ordered!) — then again, they might bring some wacko genes that no one in their right mind would want. in other words, it might be good to choose your barbarian invasion wisely.

another thing (from that hamilton paragraph above): “Often, however, the cost in fitness of such altruism and sublimated pugnacity to the individuals concerned is by no means metaphorical, and the benefits to fitness, such as they are, go to a mass of individuals whose genetic correlation with the innovator must be slight indeed.”

this goes back to something i pointed out in an oversimplification: i.e. that wildly altruistic people inevitably wind up benefitting all sorts of people to whom they are unrelated. sure they might be altruistic to a great number of people with whom they share genes in common, but they also might help a great number of people to whom they are unrelated — which is a bit of a FAIL, actually. if you’re keeping score, that is. (and Mother Nature is, btw.)

in my imagined scenario (in my oversimplifed model), the extremely altruistic individuals wound up helping twice as many unrelated individuals as related individuals. i don’t know if that ever really happens in real life, but as we saw earlier today, there are some individuals out there in the world — perhaps especially in the western world — who really go out of their way to help unrelated individuals. it’s very nice of them … but where will it get them in the end?

too much altruism?

previously: four things and which altruism genes? and technical stuff

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altruism genes and inbreeding: more over-simplification

following up on this post, here’s an oversimplified illustration of how inbreeding can make the spread of altruism genes (within a lineage?) easier.

here are two families that look like our non-inbred, randomly mating family from the previous post, but they are about to start inbreeding (oh noes!). here we have seven brides for seven brothers four sons (on the left) and four father’s brother’s daughters (on the right):

and here are all of the possible offspring of all the possible marriage arrangements they could make:

aa + aa
aa aa aa aa

aa + aA (x4)
aa aa aA aA

aa + AA (x2)
aA aA aA aA

aA + aA (x4)
aa aA aA AA

aA + AA (x4)


now, what happens in an already inbred lineage? lets say the two fathers (who are brothers) share the exact same altruism genes:

what are all the possible outcomes then?

aA + aA (x4)
aa aA aA AA

aA + AA (x8)

AA + AA (x4)

as you can see, in the second scenario (in the already inbred lineage), the possible offspring combinations are much narrower — and all the possible marriage outcomes involve at least one chance of the (grand)fathers’ altruism genes being passed on exactly (barring mutations, of course). that only happened in half (3 out of 6) of the possible marriage arrangements in the not-so-inbred lineage.

lather. rinse. repeat.

of course, this is only one possible example. just meant to be illustrative.

edit: actually, one could imagine that both of the families were just starting to inbreed, only the fathers/brothers in the second instance shared exactly the same altruism genes while the first brothers did not. going forward in time, you can see how continued inbreeding would mean that the second family’s gene pool would remain much narrower than the first. several sub-clans of this lineage could really wind up to be very inbred, having only AA members in their extended families, while only a handful would wind up that way in the first example.

previously: an over-simplification and technical stuff and four things

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