West Hunter

Genetic canalization is the extent to which an organism is buffered against the effects of mutations. Waddington said “developmental reactions, as they occur in organisms submitted to natural selection…are adjusted so as to bring about one definite end-result regardless of minor variations in conditions during the course of the reaction”. Canalization can act to buffer against environmental perturbations, and selection for resistance to such environmental noise may also produce resistance to genetic noise. But right now I’m thinking about genetic canalization.

Up to some point, the effects of not too many, not too serious mutations would be buffered: those mutations wouldn’t change the phenotype. In the same way, your typical tractor is not designed to nanometer tolerances: parts can be somewhat out of spec – up to some limit – without messing up performance. And that tractor is better than one that did require nanometer tolerances, which we couldn’t manufacture. A genotype that had high fitness, but only when everything is perfect, no mutations, could on average be competitively inferior to one that had lower peak fitness, but in which that fitness didn’t decline rapidly with increasing small-effect genetic load – a fault-tolerant design, a fitness plateau rather than a sharp peak. This has been called ‘survival of the flattest’.

Remember when I talked about compensatory mutations in small populations making up for increased load from inefficient selection? This is the just the long run of that trend: eventually compensatory mutations develop into canalization mechanisms.

Canalization is a product of natural selection. There would be stronger selection for efficient canalization in a species with more genetic load: in particular, in a species that over the long haul tended to have fairly low population size. So you might expect to see stronger genetic canalization in big carnivores than, say, mice. And you would probably see it in the great apes and hominids as well: I don’t think that we were ever numerous until recently. Surely primitive,  Oldowan-type hunter gatherers had lower population density than later, sophisticated hunter-gatherers, who had much improved methods. And those later, sophisticated hunter-gatherers weren’t exactly overflowing in numbers themselves.

So, maybe people have strong canalization. It could be that this let Neanderthals keep the show on the road for hundreds of thousands of years even though their effective population size was small. And we know that they did keep the show on the road: theory suggests that anatomically modern humans should have walked right over them on first encounter (last interglacial) – but that didn’t happen.

It might explain why load doesn’t seem to have much effect on IQ over most of the range, why we haven’t seen general IQ depression in the children of old men,

I was looking at a recent survey of current knowledge in psychological genetics. The gist is that common variants – which can’t have decreased fitness much in the average past, since they’re common – are the main story in the genetic architecture of intelligence. Genetic load doesn’t seem very important, except at the low end. Big-effect deleterious mutations can certainly leave you retarded, but moderate differences in the number of slightly-deleterious mutations don’t have any observable effect – except possibly in the extremely intelligent, but that’s uncertain at this point. Not what I expected, but that’s how things look right now. It would seem that brain development is robust to small tweaks, although there must be some limit. The results with older fathers apparently fit this pattern: they have more kids with something seriously wrong, but although there should be extra mild mutations in their kids as well as the occasional serious one, the kids without obvious serious problems don’t have depressed IQ.

Selection still acts on really nasty mutations affecting the brain, even today: people that are crazy or retarded have low fitness. We’re better at preventing early deaths from infectious disease than we used to be, but they were never super-related to IQ in the first place. Selection can change the frequency of those common variants, so differential reproduction with IQ could have happened and had consequences, probably bad ones. But how bad? I doubt if within-population selection decreased IQ by as much as a point a generation. That makes it hard to see how IQ could have declined by a standard deviation (15 points) since the Victorian era – there is no available genetic mechanism. Since it is also obvious (to anyone who has eyes) that no such change occurred, the lack of a feasible mechanism is not really a problem.

Tell about yourself. While you’re at it, tell me what you find interesting in this blog. Suggestions, too – I’ll read ’em, although I make no promises.

The New York Times just put out a story titled “Overdose Deaths Exceeded Half a Million in 2014”. As so very often on reading something in the Times, I said to myself “that’s wrong.” Because it had to be wrong – off the top of my head I knew that less than three million died from any reason each year in the US: pop of ~300 million, three score and ten, population growth, QED. No way that big a fraction died from overdoses, and of course it was wrong: the real number is something like 50k, mostly prescription drugs.

Nobody at the Times noticed it at first. I don’t know that they ever did notice it by themselves- likely some reader brought it to their attention. But this happens all the time, because very few people have a picture of the world in their head that includes any numbers. Mostly they don’t even have a rough idea of relative size.

In much the same way, back in the 1980s,lots of writers were talking about 90,000 women a year dying of anorexia nervosa, another impossible number. Then there was the great scare about 1,000,000 kids being kidnapped in the US each year – also impossible and wrong. Practically all the talking classes bought into it.

You might think that the people at the top are different – but with a few exceptions, they’re just as clueless.

I’m not even counting all the falsehoods that you’re supposed to believe in.

I have have had famous people ask me how the Ionian Greeks became so smart (in Classical times, natch). In Classical times, the Greeks – particularly the Ionian Greeks – gave everybody this impression – in everyday experience, and certainly in terms of production of outstanding intellects. Everybody thought so. Nobody said this about the Persians – and nobody said it about the Jews, who never said it about themselves.

It’s an interesting question: perhaps there was some process analogous to that which we have proposed as an explanation for the high intelligence of the Ashkenazi Jews. Or maybe something else happened – a different selective process, or maybe it was all cultural. It’s hard to know – the Greek Dark Ages, the long period of illiteracy after the fall of Mycenaean civilization, is poorly understood, certainly by me.

Suppose that your biological IQ capacity (in favorable conditions) is set by a few hundred or thousand SNPS, and that we have identified those SNPS. With luck, we might find enough skeletons with intact DNA to see if the Ionian Greeks really were smarter than the average bear, and how that changed over time.

More generally, we could see if civilization boosted or decreased IQ, in various situations. This could be a big part of the historical process – civilizations falling because average competence has dropped, science being born because the population is now ready for it…

I think we’ll be ready to try this in a year or two. The biggest problems will be political, since this approach would also predict results in existing populations – although that would probably not be very interesting, since we already know all those results.

I noticed a confused (naturally) but halfway interesting piece in SLATE, about some whacko that has concluded that men who have had their dick chopped off are not really women. Well duh. Of course, he was educated into this conclusion by talking to TERFS (trans exclusionary radical feminists). Progressives mostly think that “that gender is a matter of identity, not biology, and that refusing to recognize a person’s gender identity is an outrageous offense.” While Terfs believe that “women are are a subordinate social class, oppressed due to their biology, and that there’s nothing innate about femininity. They think you can’t have a woman’s brain in a man’s body because there’s no such thing as a “woman’s brain. As the British feminist writer Julie Bindel—a bete noire of many trans activists—put it, “Feminists want to rid the world of gender rules and regulations, so how is it possible to support a theory which has at its centre the notion that there is something essential and biological about the way boys and girls behave?”

Well, obviously it’s difficult for some ex-Navy Seal to have ‘always felt like a girl inside’ if there is no difference between male and female brains. So, will smoke now start coming out of progressive ears, as they endlessly say “does not compute”?

I doubt it. They’re perfectly capable of believing in incompatible theories – there’s no logical contradiction if you never logic in the first place. But if by some chance it does bother someone, here is the resolution:

Progressives and Terfs are both wrong: sex differences in behavior have biological roots – men and female brains are different. I mean, if male rhesus monkeys like toy trucks and females rhesus monkeys don’t, as they do, it’s hard to attribute to social pressure. Boys are much more likely to like rough-and-tumble play, blah blah blah. The stereotypes are true. Trans men aren’t little girls inside, anymore than someone with a Napoleonic complex is ‘really’ Corsican. They’re just crazy. Now that craziness probably has some biological origin, but we don’t understand it. Even if it does, it is likely that the form of that craziness is shaped by social influences, just as Malays run amok with a bloody kris rather than going postal with a Glock.

It is possible to support a theory with implications you don’t like if it happens to be true. Although maybe that’s a guy thing.

If you want to make your stupid dream real, you need to have a realistic picture of the world. If you want a society in which men and women have the same brain, or one in which feminism actually works, you would have to make it so, with advanced biological engineering. John Varley writes fiction: so did Joanna Russ.

There’s another report out on selection in the Greenland Inuit. They found clear signs of positive selection in FADS, the fatty acid desaturase gene cluster. More interesting was the discovery of strong selection on a region containing WARS2 and TBX15, located on chromosome 1. WARS2 encodes the mitochondrial tryptophanyl-tRNA synthetase, and TBX15 is a transcription factor from the T-box family that does all kinds of things – some of which (like skeletal development) can be inferred from the symptoms of people with Cousin syndrome, caused by beat-up versions of TBX15.
Probably the selected haplotype results in more brown fat, along with changes in waist-hip ratio and fat distribution. This haplotype is oddly differently from the standard human one, mostly because we picked it up from a population similar to Denisovans. It’s moderately common in Eurasia, very rare in Africa (prolly back-migration) and fixed in the inuit. It’s had hundreds of thousands of years to diverge from the standard AMH haplotype, possibly longer.

These adaptive changes picked up from archaic humans can be different (more complicated) from mutations like sickle-cell, because they can (sometimes)consist of several different linked adaptive substitutions that accumulated over a long, long time. Sickle-cell is recent, and just one nucleotide has changed. More than that, in at least some cases, such as EPAS1 (a Denisovan-origin altitude adaptation allele in Tibetans) the adaptation has progressed: it’s something a bit more sophisticated,not the first solution that came down the pike. The Tibetan adaptation is similar to that seen in mammals that have lived at high altitude for millions of years – while the altiplano adaptation is more like an exaggerated version of individual acclimatization.

Archaic humans had lived in and around the Tibetan plateau for a long time, perhaps as much as two million years. They were the go-to guys for classy altitude adaptations. In much the same way, archaic humans had lived in Eurasia during the Ice Age, freezing their nuts off, for up to two million years. They probably weren’t as good at making warm clothing as anatomically modern humans (Sharp Dressed Man), since they did not make needles. They should have had relatively sophisticated metabolic changes that adapted them to living in an icebox, adaptations worth stealing. There may be other cases like WARS2/TBX15 in the Inuit – and there may be other evolutionarily significant environmental factors (like changes in length of day) that existed in Eurasia and were largely absent from Africa.