Understanding EDAR

The east Asian EDAR mutation is screwy: it does too many things. It causes increased scalp hair thickness, shovel-shaped incisors, an increase in the number of eccrine sweat glands, and smaller breasts. Which of these seem likely to confer a few-percent advantage?  Why, none of them, of course.

Normally, an advantageous mutation does something useful and not a whole lot of anything else.  That’s because change in a trait is usually bad – it moves you away from the Darwinian optimum.  Coming up with an improved version of one trait is unlikely enough, and usually happens only in a new environment, where the selective pressures have changed.  Coming up with multiple significant changes that are all neutral is most unlikely.

Now if the side effect is in a trait that doesn’t matter anymore, you might get away with it.  For example, a mutation that has a favorable effect X while making you pale works in northern Europe.  The paleness itself may even be advantageous.

Pardis Sabeti thought that extra sweat glands might have been the advantage.  Joshua Akey suggested sexual selection – a preference for thick hair and small breasts. Kamberov thought different effects of EDAR might have been favored at different times.

They are all wrong.  Am I really supposed to believe that you needed to sweat more in ice age China than in Africa?  Breast size already varies – if for some mysterious reason human sexual fashion came to favor smaller ones,  selection on standing variation could have done the job without changing your hair and teeth and sweat glands – changes  that would almost certainly be disadvantageous..  The idea that different effects  conferred advantage at different times is also a nonstarter: any singe positive change is very unlikely, and I’m suppose to believe in several?

It’s gotta be something else, an effect that we don’t know, and it must confer a substantial advantage.

 

Posted in Uncategorized | 34 Comments

We Three Kings

A recent article says that 40% of Chinese Y-chromosomes originated from 3 men in the late neolithic.  This pattern,  fantastic success for a particular paternal lineage, has been seen before, with the Golden Family (descendants of Genghis Khan) and the Qing dynasty.   Something similar may well have happened with the big R1b and R1a lineages.

Did any historian predict this pattern?  I can’t think of one, off the top of my head. Someone who went to bed with The Empire of the Steppes under his pillow, someone familiar with the continuing high status of the Golden Family in recent centuries,  might have, perhaps.

 

Posted in Genetics | 42 Comments

Degüello

There’s a new paper out on the genetic prehistory of the Canadian Arctic. Basically, it says that existing Eskimos replaced a genetically different population less than 700 years ago, and that those earlier Paleo-Eskimos (Dorset culture) represent yet another separate migration from Asia (in addition to the PaleoIndians, the Na-Dene, and the Eskimo).  They put this in such a nice way: “the genetic continuity characterizing the Paleo-Eskimo period was interrupted by the arrival of a new population.”

Which likely means that the neo-Eskimos killed off the Dorset people.  Obviously they weren’t farmers, the usual suspects in replacement, but the new guys had a more sophisticated technology ( and probably greater numbers) ,  with  bows, large skin boats, dog sleds, whale-hunting gear, etc.  The neo-Eskimos have certainly done their share of fighting in recent historical times – they went at it hammer-and-tongs with various Amerindian tribes.

This is fairly obvious, so much so that even the New York Times and the Washington Post mentioned extermination by the newcomers as a possible explanation.  There is no mention of that possibility in the original research article, but I’m sure that some of the authors were quite aware of it. What they said is probably influenced by the fear that saying anything negative, no matter how true, might cause the Eskimos to refuse cooperation in the future.

This pre-agricultural genocide makes you wonder  just how often similar wipeouts may happened in the past.  Maybe the Gravettians and Aurignacians weren’t the same people.

 

Posted in Amerindians, Eskimo | 60 Comments

The Wrong Path

Turning Pygmy hasn’t turned out to be a very good long-run strategy. All such populations have big problems.  First, they’re vastly outnumbered by peoples that adopted agriculture.  Second, they’re short – shorter than their farmer neighbors –  and generally that has been a disadvantage in disputes. Contemporary African pygmies are ‘ hereditary servants’ of their Bantu neighbors: we have another word for that.  Maybe AK-47s will turn that around some day (God made some men big and some men small, but Mikhail Kalashnikov made them all equal, like a good Communist), but it hasn’t happened yet.  And with their small numbers, I’m not optimistic.

Moreover,  it seems that they may have incurred an intellectual disadvantage as well. They have small brains, probably the smallest of any existing human population. I found a reference claiming an average endocranial volume of 1,085  cm3 for the Aka: that’s the lowest number ever reported.  Their reported IQ scores are very, very low.  Their neighbors, who don’t score high themselves, think that the Pygmies have rocks in their head, don’t plan ahead, are irresponsible, etc  And of course they have trouble with alcohol.

A recent paper by Andrea Migliano argued that high risk, mainly from infectious disease, has selected for an accelerated life-history among Pygmies. I’m not convinced, but if she’s right, they would age more rapidly as well.  I’m not sure that is actually the case.

All this should have been obvious when modern humans were wandering into the African rainforest tens of thousands of years ago. What were they thinking?

 

Posted in Pygmies, Uncategorized | 73 Comments

Pygmification

A recent paper in PNAS talks about the  evolution of the Pygmies – or, more exactly, the Pygmy phenotype, because it seems to have happened independently in the Biaka Pygmies (west Africa) and the Batwa pygmies of Uganda.  The two groups have different genetic mechanisms for being short. Their shortness really is genetic, of course. Pygmies are mixed, to a degree: the more Bantu ancestry they have, the taller they are. And although height really is affected by nutrition, Pygmies are about six standard deviations shorter: someone of normal potential height would have had to starve to death (twice!) to be that short, and there would be lots of other symptoms of malnutrition that Pygmies don’t have.

Still, there were those who thought otherwise, presumably because they’d stuck a crayon up their nose as a kid. Way up. Environment does matter!

I noticed an interesting comment on this in Science: Michael Balter said “scientists had not been sure to what extent Darwinian natural selection is actually responsible for the Pygmy body type and how many times it has arisen over the course of evolution.”  The bit about how many times it had arisen is reasonable – that takes looking at the genotype to be sure, and indeed it has occurred five or more times (in Africa and Southeast Asia).  But there was no reason to wonder whether those changes were a product of Darwinian natural selection: that was a sure bet. Not just because it has happened multiple times in similar rain-forest environments. Darwinian natural selection is always operating.

Natural selection is not an odd, unusual, poorly understood phenomenon like ball lighting.  It is not something that last occurred 50 million years ago, like a kimberlite pipe eruption.  And, of course, it applies to human behavioral traits, which are significantly heritable. Unless you think that the optimum mental phenotype (considering costs and payoffs) was the same in tropical hunter-gatherers, arctic hunter-gatherers, neolithic peasants, and medieval moneylenders (which would strongly suggest that you are an idiot), natural selection must have generated significant differences between populations. Differences whose consequences we see every day, and that have been copiously documented by psychometricians.

This notion that ongoing natural selection is not the default – that it only happens on national holidays or whatever – is fairly common among biologists.  Obviously untrue, because you can’t even have things stay the same without ongoing selection – otherwise mutations and drift would gradually ruin everything.  Only selection lets horseshoe crabs outlast mountain ranges.

Sure, some of this is because the topic of human psychological differences makes biologists upset, or threatens to impose unemployment and/or celibacy – but it also shows up in  topics that don’t seem to have much emotional or political charge. I think that only a few biologists reject those unexciting examples of ongoing natural selection because of a realization that they logically imply other, controversial conclusions.  They do have such implications, but I think that poorly understood neutral theory plays a bigger role.

 

Posted in Uncategorized | 99 Comments

I can’t afford to think about that.

Once upon a time, a young geneticist was applying for a position at the University of New Mexico.  I believe he said something about the Ashkenazi hereditary diseases.  Someone on the faculty,  known to be susceptible to crimethink, asked him if he thought that the sphingolipid diseases (Tay-Sachs,  Gaucher disease, etc) might have something to do with selection for intelligence.  Don’t know how he ever got that notion.

The young visitor said that he couldn’t afford to think about that.  He was just starting his career, and he couldn’t afford to touch anything politically sensitive.  He said, maybe people like Harpending, with tenure and all that, could afford to think about it, but not him.

They didn’t give him an offer.  That could well have happened because they weren’t that excited about his work, or were more excited about someone else’s work, or maybe the money evaporated –  but it seems to me that although some degree of cowardice is of course required, nobody feels comfortable hearing someone loudly and publicly proclaim his utter wormhood.  We all love Big Brother, but you should really get a room.

Mind you, if he thought the idea was obviously wrong, he could have said so, and said why.  I don’t think that would have gotten him into any trouble.  But that didn’t happen.

Is there pressure – strong pressure – to avoid certain topics and conclusions in human biology?  Sure.  Another young researcher wanted to do a genetic study of students to see if those same Ashkenazi sphingolipid mutations boosted IQ.  And his advisor said, sure, if you want to become an unemployable pariah and get me in trouble. That young researcher reaction was ” fuck ‘em all –  let’s try it anyway!”.  I like him.  But it didn’t pan out, logistically.

A certain person we will not name, famous for the discovery of the double helix,  once said “Harpending must really have balls of steel, in order to take a genetic look at Jewish intelligence.”   Why should it take balls of steel?  And, for that matter, why are balls of steel so rare in academia? Do they undergo a procedure?

Isn’t there equivalent political pressure in an opposite direction?  No, not any.

People in human genetics generally know that ‘the race/IQ issue is toxic to anyone who touches it’.  They can’t risk being involved.  This is easier if their research interests lie elsewhere, true for many people. Some think that there probably is a genetic component of population differences in IQ, but simple say nothing in public.  I know some people like this.

Is this toxicity the reason for some of the silly things we hear out of these people?  Part of the reason.  I don’t think it’s anything like the complete explanation.

 

 

 

 

 

 

 

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Physics Today

I noticed an article in Physics Today, about educational techniques in physics. A couple of psychologists from Stanford were working with Carl Wieman,  talking about how to improve physics achievement in historically under-represented groups.  Seldom have have I seen such bullshit.  They explain that intelligence isn’t a fixed quantity – people aren’t ‘smart’ or ‘dumb’.  But if your teacher thinks that intelligence is ‘fixed’,  or if you do, you’ll do badly – but not if you’re a white or Asian male , who are somehow immune to these effects.  As an instructor, you have to careful not to let the under-represented know that you’re making special efforts on their behalf, because then they’ll think that you’re doing it because they’re dumb – and then they’ll be dumb, presumably because that collapses the wavefunction.   Somehow these educational techniques only work if the practitioners believe in them (really, REALLY believe in them).  Unlike penicillin or machine guns.

Carl Wieman is a smart guy, but on this subject, he’s pathetic. I have to wonder about how how wide his slice of life has been.  Has he never watched someone break his heart trying and failing to master some subject that others sailed through without breaking a sweat?  Has he ever actually known someone dumb? Even someone of average intelligence? Talked to them? Listened to them? Has he ever read a single book on psychometrics?  (that’s asking a lot, but after all, he IS a Nobelist.)

I am reminded of a couple of anecdotes concerning Richard Feynman. When his son was young, Feynman told him complicated stories  that, when finally understood, were set in some odd bur physically real environment – say in the microworld.  Those giant trees in the cavern were actually nose hairs, etc.  He tried this with his daughter, but she didn’t like it.  She wanted him to read the stories in the book, over and over, just as they were written.  He decided that people were just different – which is true. It is even more true when the son is the offspring of one of the smartest guys in the United States and the daughter adopted, and thus almost certainly NOT the biological offspring of one of the smartest people in the United States.

Brazil is another example.  Feynman visited and taught in Brazil.  The girls on the beach seemed right, but something else seemed wrong: ” So I tell them that one of the first things to strike me when I came to Brazil was to see elementary school kids in bookstores, buying physics books. There are so many kids learning physics in Brazil, beginning much earlier than kids do in the United States, that it’s  amazing you don’t find many physicists in Brazil – why is that? So many kids are working so hard, and nothing comes of it.”  I don’t believe that a huge fraction of Brazilian kids were studying physics, or for that  matter a higher fraction than in the US at the time.  But I do believe that the average IQ in Brazil at that time was a good deal lower than in the US, because that’s what every test (and life itself) shows.  And maybe that had something to do with Feynman’s observations.

 

 

 

 

 

 

 

 

 

 

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