Centum and Satem

I may well be wrong, but there’s no point in waiting until they dig up and sequence every last body in Eurasia. Time to stick my neck out.

Here’s my current best guess concerning the Indo-European expansion:

It all started pretty far to the East. There, some crazy locals first tamed the horse.  I’m thinking that they were something like the Botai culture, riding and hunting horses, but not farmers. They may well have milked those horses – by the way, horse milk is much richer in lactose than human or cow milk.

These early horsemen were genetically similar to the Ancient North Eurasians, or as those who know have dubbed them, Sibermen.

Having horses made them natural raiders, let them expand.  Lactose tolerance might have helped.

A fraction of them conquered some farmers (a mixture of Middle Eastern types and others similar to western hunter-gatherers)  in the eastern Ukraine,  imposed their language, and roared into northern Europe.  This accounts for the Centum languages: they have probably some additions from whatever language those Ukie farmers were speaking. Some people from this group (Tocharians) must have made a wrong turn and eventually ended up in Western China. Even today some Uighurs show the mark of those red-headed strangers.

OLYMPUS DIGITAL CAMERA

But that centum expansion  didn’t come first. Other, earlier kinds of Indo-Europeans had already destroyed the old EEF culture in the Balkans – and although they seem to have had some ANE ancestry, they apparently had very little WHG ancestry.  You see mixtures of EEF and ANE in Greece and Albania, but almost no  WHG.  This has to be the result of a separate, early Indo-European expansion.  Looks as if this might have gone on into Anatolia –   the Hitties, Luwian, Palaic.

Nor was it the last. There must have been some peoples in the real Indo-European homeland (farther to the east than the Yamna culture) who had not yet conquered a bunch of motley farmers and had remained mostly ANE.  Considerably later, now charioteers,  some of them moved south, conquered some more Armenian-like farmers (the Bactria-Margiana culture, BMAC, located in the southern part of what used to be Soviet Central Asia, now Trashcanistan) (but no WHG types) and then went on to conquer India and Iran.  Some ended up in odd corners like Nuristan and the Chitral Valley: here’s a young Kalash boy.

Blue-eyed-Kalash-child

Both the European Centum expansion and the later Indo-Aryan expansion carried the same lactose-tolerance mutation., which has never been found in aDNA from the EEF farmers. Of course it could have been around in Old Europe, just still rare, but the simplest explanation for finding the same common mutation in Europe and north India is that it was spread by the Indo-Europeans themselves.

The WHG hunters had blue eyes, the same mutation as today, while the early European farmers had SLC24A5, but as of yet I’ve not seen any ancient examples of the  alleles that give varied hair color in Europeans.  Blondes and redheads are rare in Basques and Sardinians – I’m wondering if the ANE are the source.

Posted in Dietary adaptations, European Prehistory, Genetics, Indo-European, Linguistics | Tagged , , , | 77 Comments

Yamna and Corded Ware

I hear some interesting things from the recent ASHG conference, mostly from Razib Khan. It seems that the dead have spoken again: it turns out that the genetic transition in northern Europe  coincides with the advent of the Corded Ware/Battleaxe culture – and the Corded Ware folks were invaders from the Yamna culture. If I got this straight, Germans today are about 70% Yamna. And if that’s so, I’ll bet that they were even more Yamna in, say, 2800 BC.  I think the previous EEF inhabitants fared poorly. It may be that  the people of Old Europe left scarcely a trace of their blood in the veins of their conquerors – in the north. Corded_Ware_culture

The Yamna, were themselves a fusion of peoples – part eastern hunter-gatherers (with a large fraction of ancient Siberian) and part a more Middle Eastern-ish farming population, similar to Armenians.

1174px-Yamna-en.svg

Which fits those old notions about the Indo-Europeans starting out as a group of warriors and magician/priests who conquered and assimilated a race of farmers… the Aesir-Vanir war, the sobbin’ women,  etc.  J. P Mallory says “the three estates of of Proto-Indo-European society were fused only after a war between the first two against the third.”  This implies that the Sibermen were on top: which also fits the big expansion of R1B and R1A, both of which turn out to be about 5,000 years old.

Like I said in Silver Blaze, they’re working out the origin and scope of the Indo-European expansion.

Posted in European Prehistory, Genetics, Genghis -Khan effect, Indo-European | 44 Comments

Ketosis as a way of life

There’s a new article out in ASHG that discusses a regional selective sweep in CPT1A, carnitine palmitoyltransferase 1A, which plays an essential role in fatty acid metabolism. A mutation has become extremely common, with a gene frequency > 50%, in northeast Siberian populations, Eskimos, and Aleuts.  This happened even though the c.1436C>T mutation has some negative side effects, such as reduced fasting tolerance and, apparently, a higher risk of infant death.

It looks as if this variant conferred significantly higher fitness (~15%) over the past few thousand years and has increased very rapidly.  Almost certainly, this has something to do with traditional diets in these areas, in which fat provided 80-85% of energy and protein 15-20%, with hardly any carbohydrates. We’ll know more about the biochemical details of how this mutation works when someone makes a mouse model.

This could only happen in the Arctic, where agriculture is impossible, plant foods limited, and marine mammals use blubber as insulation.

It illustrates an important point, mentioned in our book: an ancestral diet might have some payoff, but likely the appropriate diet would be the foods eaten by your ancestors, not somebody else’s.

Posted in Dietary adaptations, Eskimo, Genetics | Tagged | 64 Comments

Ust’-Ishim & the Old Race

There’s a new report out in Nature, on the DNA results from a 45,000 AMH skeleton found in Western Siberia.  It’s the oldest radiocarbon-dated modern human outside Africa and the Middle East.

The Neanderthal admixture is there,  about the same amount as today, but in larger blocks than in people today.  Less shuffled, so we now have a better estimate on the admixture date: 50-60,000 years ago.  The skeleton confirms the new lower estimate of the human mutation rate, about 1.2 x 10-8 per generation.   He’s equally related to Andaman islanders, Amerindians, Han Chinese, that Mal’ta Siberian ANE boy, and Old European hunter-gatherers (La Brana), but somewhat more distant from modern Europeans (French and Sardinians), because of this basal Eurasian component from the Middle East (found in the EEF, the original farmers of Europe).  These Basal Eurasians would have had to split from the AMH population that did the main expansion out of Africa before they left, so the split must have been well over 60,000 years ago. That doesn’t tell us exactly when the Basal Eurasians left Africa, however.  Could have been as long ago as the Shkul and Qafzeh skulls, roughly 100,000 years ago, could actually have been far more recent.

We know that there was an expansion of modern humans into the Middle East ~100,000 years ago – so the simplest explanation is that the Basal Eurasians are descended from that early expansion. Otherwise we have to posit three different expansions of modern humans out of Africa, one of which failed after a while. If they left that early, looks as if the Basal Eurasians didn’t sufficient moxie to displace archaic humans over most of Eurasia (while the later dispersal did) .  On the other hand, they do seem to have invented agriculture.

Finding a decent-quality ancient sample that is a good representative of those Basal Eurasians, as the Mal’ta boy is of the ancient Siberians, would sure help clarify things.

Chris Stringer is quoted as saying that the study offers compelling evidence that living non-Africans descend from a group that left Africa about 60,000 years ago – but in fact it strengthens the case that there were in actuality at least two different successful expansions of anatomically modern humans out of Africa.

Posted in Archaic humans, European Prehistory, Genetics, Neanderthals | Tagged | 29 Comments

The Experts

It seems to me that not all people called experts actually are.  In fact, there are whole fields in which none of the experts are experts. But let’s try to define terms.

You might say that an expert is someone who knows more about a subject than some random dude off the street.  That could mean that the man in street typically had false ideas [worse than a coin toss] about the subject, while the expert admits that he knows nothing, but let’s aim higher.  We’ll define expertise as something that not everyone has, that gives you at least some predictive value (possibly a lot), and sometimes the ability to control outcomes.  Such real expertise can be proven experimentally.  Generally, that kind of expertise can be acquired (the wisdom of the Occident), but it may be that not every one is talented enough to be very good at it.

Then again, by a different but occasionally useful definition, an ‘expert’ is someone that society considers an expert, whether he actually has any predictive power or not.  We denote that social position by quotes.

Sometime no-one has any any predictive ability: some stuff, nobody understands.  There’s a good chance that we will still have some some socially-approved ‘experts’ on that subject.

You can have a situation in which expertise exists in some field exists  – there is a knowledge set that can confer predictive value, and at least some people have that knowledge – while the people generally considered experts by society (‘experts’)  are useless, or worse than useless.  You can even have situations in which virtually everyone – except for the ‘experts’ – has expertise on a subject.  You can have negative time trends: things go from a situation in which virtually everyone knows certain facts to  one in which the overwhelming majority of people – including the ‘experts’ know things that just aren’t so.

There are plenty of examples.  At the high point of Freudian psychoanalysis in the US,  I figure that a puppy had a significantly positive effect on your mental health, while the typical psychiatrist of the time did not.  We (the US) listened to psychologists telling us how to deal with combat fatigue: the Nazis and Soviets didn’t, and had far less trouble with it than we did.

Fidel Castro, a jerk,  was better at preventive epidemiology (with AIDS) than the people running the CDC.

In the 1840s, highly educated doctors knew that diseases were not spread by contagion, but old ladies in the Faeroe Islands (along with many other people) knew that some were.

In 2003, the ‘experts’ ( politicians, journalists, pundits, spies) knew that Saddam had a nuclear program, but the small number of people that actually knew anything about nuclear weapons development and something about Iraq (at the World Almanac level, say) knew that wasn’t so.

The educationists know that heredity isn’t a factor in student achievement, and they dominate policy – but they’re wrong.  Some behavioral geneticists and psychometricians know better.

In many universities, people were and are taught that really are no cognitive or behavioral differences between the sexes – in part because of ‘experts’ like John Money. .  Anyone with children tends to learn better.

Along these lines, I’ve read Tetlock’s book, Expert Political Judgment. A funny, funny, book. I will have more to say on that later.

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The Advent of Cholera

Most of this is stolen from William MacNeill’s Plagues and Peoples.

Cholera seems to have existed in the Ganges delta for a long time, but it only spread to the rest of the world fairly recently.  An unusually severe epidemic broke out in 1817: it spread by ship to Sri Lanka, Indonesia, Southeast Asia, China, and Japan between 1820 and 1822.  A British expeditionary force brought it southern Arabia in 1821, and from there is filtered down the east coast of Africa.    It moved up into the Persian Gulf, reaching Iraq and Iran, then Syria, Anatolia, and the Caspian.

In 1826 a new epidemic moved even further, spread through Europe and North America.

It had been some time since the last outbreaks of bubonic plague, and most of the techniques for limiting its spread had lapsed. Some places still remembered: Marseilles, for example, had experienced a late outbreak of plague in 1721 and annually commemorated it.

Two main factors interfered with an effective policy response to cholera (not counting ever-present human stupidity and obstinacy): bad science and 19th century liberalism.

Scientists at the time had convinced themselves that the germ theory of disease was just wrong.  Yellow fever’s decimation of the French force in Haiti made it important, and when yellow fever hit Barcelona in 1822, French scientists were all over it. They concluded that there was no possibility of contact between yellow fever victims in Barcelona, and ruled out contagion.  Mosquito transmission didn’t occur to them.

Worse yet, they generalized their error: they concluded that contagion was never the answer, and accepted miasmas as the cause, a theory which is too stupid to be interesting. Sheesh, they taught the kids in medical school that measles wasn’t catching –  while ordinary people knew perfectly well that it was. You know, esoteric, non-intuitive truths have a certain appeal – once initiated, you’re no longer one of the rubes.  Of course, the simplest and most common way of producing an esoteric truth is to just make it up.

On the other hand, 19th century liberals (somewhat like modern libertarians, but way less crazy) knew that trade and individual freedom were always good things, by definition, so they also opposed quarantines –  worse than wrong, old-fashioned ! And more common in southern, Catholic, Europe: enough said! So,  between wrong science and classical liberalism, medical reformers spent many years trying to eliminate the reactionary quarantine rules that still existed in Mediterranean ports.

The intellectual tide turned: first heros like John Snow, and Peter Panum, later titans like Pasteur and Koch. Contagionism made a comeback.  I am not an expert on that history, but I think that the classical liberals didn’t argue that it would have been better for people to die than survive due to state-imposed public-health methods.

Posted in Uncategorized | 115 Comments

The Coming Plague

Laurie Garret has an article out in the Washington Post.  She say that there’s no point in trying to block the spread of Ebola by travel bans.

The problem is, she’s full of crap.  Look, there are two possible scenarios.  In both of them, r, the number of new cases generated by each case, is greater than 1 in parts of West Africa – which is why you get exponential growth, why you have an epidemic.  If r < 1.0, the series converges – a case generates a few extra cases before dying out.

Everything we know so far suggests that even though it is greater than 1.0,  r in West Africa is not all that big (maybe around 2), mostly because of unfortunate local burial customs and incompetent medical personnel.

It seems highly likely that r in US conditions is well under 1.0 which means you can’t get an epidemic. However,  r is probably not zero.  It doesn’t mean that you can’t get a few cases per imported case, from immediate contact and hospital mistakes.  As an example, suppose that on average each case imported to the US generated a total of two other cases before dying out (counting secondary, tertiary, etc infections).  Then, on average, the number of US citizens infected would be twice the number of infected visitors.

Now suppose that a travel ban blocked 80% of sick people trying to fly here from Liberia.  We’d have 80% fewer cases in US citizens: and that would be a good thing. Really it would.  Does Laurie Garret understand this?  Obviously not. She is a senior fellow for global health at the Council on Foreign Relations, but she is incompetent.  Totally useless, like virtually everyone else in public life.

We hear people from the CDC saying that any travel restrictions would backfire, but that’s nonsense too.  One might wonder why they say such goofy things: I would guess that a major reason is that they were taught in school that quarantines are useless (and worse yet, old-fashioned), just as many biologists were taught that parasites are really harmless – have to be, because evolution!

In the other scenario, r > 1.0 in US conditions as well, or at least is greater than 1.0 in some subsets of the US population.  This is very unlikely- even more unlikely considering we can adjust our behavior to make transmission less likely.  But suppose it so, for the sake of argument.  Then you would want – need – to stop all travelers from the risky regions, because even one infected guy would pose a huge risk.  Some say that blocking that spread would be impossible. They’re wrong: it is possible*, although it wouldn’t happen, because we’re too crazy.  In fact, in that scenario, we’d be justified in shooting down every plane that _might_ carry an infected passenger.  This scenario is the one that fits Garrett’s remarks, but if she really believed it, she would be frantically buying canned goods and finding a cave in the Rockies to hide her family in.

*the Atlantic is pretty wide.

Posted in Uncategorized | 217 Comments