Origin of the Indo-Europeans (and Hittites!)

(I should edit, but I'm too tired.)

Okay, I'm ready to have a go at this. I mentioned the new preprint The Genetic Origins of the Indo-Europeans, that names everybody who is anybody* in this branch of anthropology a few weeks ago. I am told it is reasonable and easy to understand, but it takes me longer than others, maybe. The subsequent reports I see want to start in media res, at a point we can say "yup, those are definitely Indo-Europeans." They are definitely better informed and probably smarter than I am, and they usually start with discussing three clines of genes around Central Asian rivers over 5000 years ago. From our vantage point these rivers seem close together, but the Dniester is about 1000 miles west of the Volga. Not neighbors, really.

But being both arrogant and stupid, I would rather tackle this chronologically, starting almost 7000 years ago. 6500, anyway. Yet just to get those clines out of the way, it is two smaller ones and one big one, and they all have a fair bit of Caucasian Hunter Gatherer genes in them. They were on Ukrainian and Kazakh rivers.

One of my first posts in 2006 was about the controversy of the Indo-European homeland. I vaguely put it in the Marija Gimbutas versus Colin Renfrew camps. I will not link to it, because I was being a smartass and it provided little good information.  (Hard to believe, I know.) The Anatolian branch of Proto-Indo-European does not share characteristics with all the other branches, from which we conclude it split off first.  This would be the Hittites, Lydians, Luwians. Their language says they are related to the people of the Pontic Steppe north of the Caucasus Mountains. Yet they have not seemed to be part of the explosive takeover of most territory from Mongolia to Ireland over the next few millennia, including a section from the Altai to Hungary very quickly.

We used to put the split between these first two groups around 4000BC. This has been nudging back and 5000 BC is now in play.  The paper should actually be called "The Genetic Origins of the Indo-Europeans and the Hittites," because we cleared up both in this one. There had even been a theory that the Anatolians were the first speakers, and the later groups which went on to dominate the world split off from them incurrent Turkey and migrated north. The earliest dates for the language PIE rather than the people were 4500 BC, and now that is nudged back as well.  It now looks that a number of tribes played a small genetic role in mixing with Caucasian Hunter Gatherers across a wide range.  In fact, it's a wider range every time we look. Sometimes we name a group according to where we first found it, then find out to our embarrassment they actually lived a lot of other places as well, and the name doesn't fit so neatly. Even before its Yamnaya (Russian for "pit-grave") segment started taking over Eurasia in 3400BC, CHG covered a lot of territory.  To make it clear, all Yamnaya has a lot of CHG in it; but not all CHG turned into Yamnaya. 

All groups we can find evidence for look like they engaged in a great deal of violence. Popularisers and even real anthropologists can forget themselves and see some groups as more peaceful, but this is only in contrast to the insane levels of violence of the young Yamnaya. (That's us, remember.) Even Gimbutas, who has been largely vindicated and I admired greatly, spun a tale of the kurgan peoples overrunning more peaceful matriarchal societies from Asia into Europe. Pop culture references to The Goddess as a concept date from her book on the subject in 1974. Yet it turns out they were also plenty patriarchal and violent after all, now that we have better archaeology. 

I should do a post on why (some of) both feminist and antifemist myths of the current day would like there to have been societies that showed greatly elevated status of women in the past, even though the evidence is sparse.

Back on task...on to the clines.  So by about 3600 BC there is this stew of various tribes admixing in the usual patrilocal way, so that women are moving from the tribe of their birth to just about anywhere up and down the river or less often, east and west between rivers. While fascinating to the specialist, the three river clines are unremarkable in general at that point.  They all have a lot of Caucasian Hunter-Gatherer in them, but CHG is mixing with a whole bunch of other groups. In the granddaddy of the clines, the Caucasian Lower Volga, it is mostly just CHG. (It has some older Neolithic West Asian in it, but new genetic bits of that had stopped coming in long ago.)  They have already achieved dominance and pushed the other groups - and definitely the males - out. We might be suspicious that this is the core Yamnaya, poised to explode out and conquer the world.  Yet that seems slow in coming. If their dominance is that thoroughgoing, there must have been considerable violence.  Yet not the signature violence the people who became us were noted for.  

In the two other clines, there is still a lot of general mixing going on, even though the CHG are more numerous. In the northern Volga, they are mixing with their distant cousins the Eastern Hunter Gatherers. EHG was itself a mixture over the previous millennia: Ancestral North Eurasians, Paleo-Siberians, Khvalynsk, and even some Western Hunter Gatherers. They mixed with the more purely CHG downriver.

In the Dnipro-Don cline to the West, the CHG that were already there had been mixing with Ukrainian Neolithic Foragers for a few centuries, if not more. So it is already 50-50 CHG and UNLF when the that big group from the Lower Volga starts to move in, expanding a considerable distance westward through the Don, Dniper, and eventually Dneistr Valleys. 

If you are looking for a workable analogy for all these tribes mixing, separating, moving back together in different configurations, all the while maintaining some main threads, compare it to the development of English. It comes out of a group of languages in Northern Germany and Denmark that were already moving back and forth, trading wives, fighting in each other's war bands at times and becoming more similar - then they move across the water to Britain where they pick up some local wives and local words, but settle in different places along the shore. As they move from raiding to settling, they starting trading wives of similar language again, but the kaleidoscope has turned. Next, one batch of Vikings comes in, then another. The important people start picking up some Latin. Then the Normans come in and it starts all over.

I was tempted to add a layer of complexity,  I slapped myself silly.

So there are some precursors to the world-conquering aggression, and they seem to be from the CHG. Should we conclude that the explosion out into the Steppe in 3300BC, The Horse, The Wheel, and Language, comes from some subgroup of CHG in the CLV cline?  That would look like the way to bet. But everyone shakes their head, winces. The y-haplogroup pieces are not convincingly in place. Once the fuel is piled up the spark might come from anywhere. We have 90% of the story, but that seems to be a bit weird and elusive.

But once it starts, there is no more talk about mixing anymore, certainly not on the y-chromosome.  The Yamnaya eliminate all before them.  All this kaleidoscopic complexity ends for a few generations. In every conquered land some form of calm returns in even the next generation as people need to forage, even farm again.  The strike-force of dog-eating males trying to make a name for themselves moves on to the next raid, but the people left behind have to start getting along and admixing again.  Yet now, they are admixing with much nearer relatives, also recent descendants of the invasion. Genetically, the complete autosomal DNA is a lot more similar. And simpler. They may come from different river-groups and thus different clines, but they are still closely related. It's something like 5000 miles from western Mongolia to Hungary but in 4-500 years you've got fifth-cousins in both places. There is a single example of 3rd-cousins that far apart. 

I am leaving out the Tocharians and the early Iranian farmers, fascinating as they are.  Maybe some other time.

One last thing.  As most of this audience is European, you are going to care more about what happened as this whole 300-1000 year long war party moved west all the way to Ireland, and eventually America. That's another story, but I can tell you how this study bears on it. We had strong suspicions that the Corded Ware culture was largely Yamnaya, and it turns out to be 75%.  That's including a few generations of captured wives, so they must have been bringing a few Yamnaya women along as well.  the succeeding Bell Beaker Culture, another 500 years on, is still 60% Yamnaya. We suspected.  Now we know.

And that's Europe.  The Celtic, Germanic, Italic, Slavic, Baltic branches all come from that. So if your Irish grandmother married an Italian or a Pole, it's all still descended from a few thousand people from around Volgograd or Astrakhan about 6000 years ago. About 10% of all the genes in all the people in the world come from that small group. The Greeks split off early - so did the Armenians and Albanians.  They are Yamnaya but not Corded Ware/Bell Beaker. And of course the Uralic groups, the Hungarians, Finns, Saami, and Estonians are not even Indo-European.  But everyone else in Europe is. 

Heckuva founder effect.

*Iosif Lazaridis, David Reich, Nick Patterson, David Anthony - even I recognise the names!