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The world after the great mixing

F2.largeelam03
In my free moments I have been reading R. Scott Bakker’s The Great Ordeal, as I needed to take a break from Congo: The Epic History of a People (I stopped before the Great War). As you might guess the latter is not a ‘feel-good’ work. And to be frank, The Great Ordeal is probably not the best choice to lighten the mood as a change of pace. It is one of the darkest and philosophically textured examples of the fantasy genre I’ve ever encountered, but that’s not surprising given Bakker’s previous works, and his background as an academic philosopher. Though the series does not indulge in as much graphic and visually rich descriptions of death and gore as George R. R. Martin’s A Song of Ice and Fire, it’s more deeply haunting and horrible. If Martin deals in shades of gray, from the honorable lightness of Jon Snow to the black depravity of Ramsay Bolton, Bakker’s characters seem to be swallowed by a blankness of color. Amorality rather than immorality.

Martin is a master of creating vivid characters with deep color who operate in a world of frenetic and engaging activity (at least up until the third book, when the plot was relatively fast). In contrast, Bakker’s plotting and characterization are both inferior, but that is in part because he gives more space over to a broader philosophical and moral framework, which hangs heavily over the whole narrative. Golgotterath and the Inchoroi are more memorable to me, alive in my imagination, than assorted protagonists swept up along the tides of history over the course of Bakker’s five books so far.

Where R. Scott Bakker excels, and where he rivals Tolkien in my opinion, is world building on a cosmic scale, complete with a well thought out mythos for humanity in his Secondary World. Bakker’s vision exhibits a great deal of verisimilitude, traversing humanity’s Bronze Age to the medieval period in ~4,000 years. The main actors within the narrative action are people from three of the races of men, of whom there are five total, and whose history goes back to an event termed the Breaking of the Gates, as humanity streamed into the western portion of the continent on which they reside, and engaged in a campaign of genocide against the Nonmen and their human servile caste, the Emwama.

Why am I regaling you with the narrative of a fantasy book series? Because the recent results out of ancient DNA and historical genetic inference of human prehistory suggest that the ‘make-believe’ narratives of epic fantasy may actually be an appropriate model of the formation of human populations in the wake of the Holocene. A friend of mine half-seriously quipped that the last 200,000 years of human history are a matter of collapsing ancient population structure. In fantasy novels often main characters themselves are exemplars of such broken population structure; the ‘half-blood’ trope as it were.

As a primal and backward looking genre fantasy dispenses with the need for a liberal individualist ethical framework, as historical relativism allows us to “put ourselves in the place” of protagonists whose motives and concerns are profoundly alien to moderns, albeit often with a sympathetic and contemporary twist. Jon Snow’s life to a great extent is motivated by his need to prove himself despite his bastardy. The specific motivation here would be hard to understand today, as legitimacy is not legally or normatively privileged as it has been historically, but the general need to find a place for yourself is one we can empathize with. Snow’s situation within a world of great noble houses and warring polities divided by region and language is one which most moderns are not comfortable with, but he is no revolutionary who yearns to overthrow the old regime. On the contrary, he is likely to play a large role in its maintenance and perpetuation.

Sargon_of_AkkadThe meteoric rise of individuals from a humble station in the context of a static and hierarchical world are not aberrations on a world-historical scale. Sargon of Akkad, the first recorded emperor, whose dominion spanned multiple polities, was from a humble background. Gilgamesh, the scion of a noble family may be semi-mythical, but Sargon was a real person. On the edge of history, but a real person. In a world of corporate entities, defined by group identity, affinity, and affiliation, his success occurred though co-option of a system of city-states with roots over 1,000 years old at that point.

Sargon’s world is one whose outlines we are only vaguely aware of. There are many lacunae, not least of which the origins of the Sumerian people, who served to Sargon’s Akkadians the role of cultural progenitors. A linguistic isolate, the origin of the Sumerians is an unresolved mystery to this day. The end of the Sumerian cultural hegemony occurred in part due to the depredations of the Gutians, people from the hills of what is today Kurdistan, and rivalry with the people of Elam, from modern day Khuzistan.
Elam-mapThe linguistic affinities of the Gutians are unknown, while the Elamites, like the Sumerians, seem to be part of a linguistic isolate.

Much of this ignorance has to do with the importance of literacy in history. What we know about Elam is often through a Mesopotamian lens. The people of Sumer and Akkad, and later Babylonia and Assyria, saw Elam as the great enemy, the Persia to their Rome. The Gutians were a coalition of tribes from the mountainous areas to the east of Mesopotamia, and so had no real indigenous literate tradition. They do not even seem to have a distinctive enough archaeological tradition to trace their migrations.

F4.largeWithout text and material where does that leave us? Obviously we have a new method: ancient DNA. With this method one can infer demographic change by looking at patterns of genetic variation. The genetic relationship of various peoples who are “mysterious” to us today with modern populations will give us great insight. I predict that when the first results come back from Elamite Iran there will be a strong affinity to peoples in southern Pakistan, especially the Baloch and Brahui, as well as connections to India more broadly, above and beyond the expected local continuity.

Last week Science published a new paper on ancient Iranian genomes, from a period thousands of years before what I discussed above, Early Neolithic genomes from the eastern Fertile Crescent. It’s open access, so you can read it yourself, and I encourage you to do.

What makes this paper different from what has come before? Two things. The first is minor: better sampling. In particular, they have better regional sampling. For example, Iranian Zoroastrians (the link has plink format files). Second, and more important, they have at least one sample at 10x or more coverage. This means they can use haplotype based methods and make better calls on genotypes. It’s much more extensive in the supplements, but the authors discuss the functional characteristics of these populations more than in the earlier papers because of access to higher quality whole genome data. You need to be more confident at a specific locus when inferring function from that locus, than you need to be across the whole genome.

The phylogenetic portion reinforces what the earlier work argues: there were two great tribes of founding farmers who brought agriculture to North Africa, and Western & Southern Eurasia. Though the “cradles of civilization” were often in riverine landscapes, the agricultural revolution began in the Near East in the uplands, which would later become backwaters. Only here could primitive dryland agriculture take root in the desiccated landscape. This was the “Breaking of the Gates”.

There were, it seems, two major phases. The first phase was expansionary. The western farmers pushed outward to Europe and North Africa. The eastern farmers pushed toward South Asia and Central Asia. But look at the position of Iranians in the PCA, and the affinities within Iran. Modern Iranians are much more west shifted than you might expect from perfect continuity. Additionally, the haplotype affinities of populations to western vs. eastern farmers shows that Iranians today have much more affinity to western farmers than Iranian speaking people from Pakistan, especially the Baloch and Makrani in the southwest of the country. This is because there was a second phase: the great scrambling, when reflux from the west into Iran, and vice versa, erased the great division.

In the initial expansionary phased a stylized model was probably as good as any model. The world was dominated by hunter-gatherers, whose social-political ability to scale and organize was minimal. The farming populations probably began to organize chiefdoms rather early, and the spread of their lifestyle was to some extent at the tip of the spear. The hunter-gatherers fled, or were rapidly assimilated as subordinates, losing their cultural distinctiveness. But the next stage after the chiefdoms were more complex arrangements, which might transcend tribal loyalties, especially when one’s tribe spanned a continent.

A close look at the map shows that the Baloch and Sardinians have more affinity with these two ancient peoples than many of the groups which today occupy the Middle East. Why? Mostly because they are distinctive in being less subject to the reflux migrations in the wake of the Neolithic. And, if you look at Europe and South Asia, you can see that Indo-Europeans also left a stamp on these areas, by mediating gene flow from these tribes into areas where the other tradition had been dominant. Northern Europe is less biased toward western farmers than Southern Europe. Within South Asia, the most skewed bias toward eastern farmers are the Baloch, who happen to co-inhabit territory with a non-Indo-European speaking population, the Brahui. These Dravidian speakers are basically indistinguishable from the Baloch. Among the other groups, the Vishwabrahmin are biased toward eastern farmers. In contrast, the Tiwari, North Indian Brahmins, are more balanced. I believe this is because the Indo-Aryans brought western farmer ancestry with them from the steppe.

Rather than talking about the phylogenetic aspects anymore, I want to move to the functional considerations. It seems that the ancient eastern farmers did not have many of the adaptations that we associate with farmers. This is entirely logical. Much of our genetic character is the product of cultural changes, rather than cultural changes being the product of our genetic character. The null hypothesis should be that hunter-gatherers who had just taken to farming are basically like hunter-gatherers who adapted a new lifestyle.

But there are some intriguing elements of the pigmentation genetics, a topic I know a fair amount about. The results from this paper show that the derived variant of SLC24A5, the largest effect pigmentation allele we know of, was segregating in these farmers. This is not surprising. It was segregating in western farmers at high frequency as well. Among Caucasian hunter-gatherers, and even among hunter-gatherers from Mesolithic Sweden. It was, though, not so much found among Western European hunter-gatherers. It is totally fixed in Europe today in the derived variant. Curiously, the authors mention that SLC45A2, another skin-lightening derived allele, which is much more concentrated in Europe, has been found segregating in Neolithic Aegeans. So it may be that the two major skin-lightening alleles were introduced by western and eastern farmers. Finally, the allele known to produce blue eyes in Europeans, found in high frequencies in Mesolithic European hunter-gatherers, was also found segregating in WC1. WC1 is the highest quality genome in their ancient data, so this seems a likely inference.

What this tells us I think is that skin-lightening alleles have been segregating at appreciable frequencies for long time. They have a deep history. Periodically, a particular haplotype gets targeted for selection, and a sweep occurs. Personally, I am more and more leaning to the hypothesis that a diversity of functions and characteristics are the targets of this selection, with the phenotype often being a side effect. What is even more intriguing to me is that the peoples as distinct as Sardinians and Baloch don’t actually look that different physically. The great reflux even affected them, and with it perhaps came alleles which were selected upon and produced a relatively uniform phenotype from the Atlantic to the Indus?

Much of the prior understanding of history and prehistory has been driven by a banal and workaday conception of progress and change. Proponents of demic diffusion imagined stateless villagers pushing outward. Diffusionists assumed that techniques and material would flow along trade routes. There were no great disruptions, rather, there were evolutions and continuities.

That is not what ancient DNA tells us. In another context I’ve mentioned that ISIS is appealing to some because of its “heroic” narrative. Similarly, the origins of modern humanity may be much more heroic than we’d have thought. We the descendants of humans who crossed in Australia. The descendants of humans who finally made it to the New World. Would it be any surprise that nearer prehistory was as ground-breaking and tumultuous?

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