It all began in the hillocks to the north of the plains of modern Syria and Iraq. Agriculture that is. Or more precisely, the West Eurasian package which would wash all the way to the Atlantic, and deep into Eurasia, and in innumerable ways influence most human societies. The standard model until recently was that this was a cultural, rather than genetic, revolution. That is, the idea of agriculture took root among people as they emulated their successful neighbors. An analogy here can be made to writing. Early Egyptian forms of what became hieroglyphs much more resemble Mesopotamian cuneiform than they later did. The idea of writing was critical, to the point where we know that it occurred at least one other time (East Asian writing may have been independent, there is debate about this).
But there’s a crucial difference. Writing is complex, but the idea is simple enough, symbolic representation of language, that one can imagine imitating it. Additionally, originally literacy was a monopoly of a small class of scribes. One can imagine that these people were highly skilled and perhaps initially mobile, but they made little demographic impact among the polities which they traversed. Agriculture is different. It is not just a technology, but it is a lifestyle. One of the insights of Peter Bellwood’s First Farmers is that the there aren’t too many instances of modern ethnographic instances of hunter-gatherers or nomadic populations happily settling down to the farmer lifestyle. The work of cultural evolutionists more recently reinforces the fact that there is a great deal of tacit norms which are both functionally critical toward many traditional lifestyles, and, whose utility and contingent integration are not reflectively understood by those who practice a given lifestyle.
That’s just a way to say that many people do what they do because they’re going through the motions of traditions which they have internalized over their whole life, and they couldn’t even tell someone else in any rational way why they were doing what they were doing. If you were trying to imitate them you’d probably discard a lot of functionality without understanding its importance to the whole system.
So how did farming spread? It didn’t, farmers did. Endogenous population growth in the simplest formulations resulted in a natural replacement of hunter-gatherers with farmers. More recently works such as War Before Civilization have convinced me that early agriculturalists engaged in a lot of inter-group competition. In other words, it wasn’t just passive demographic replacement, but proactive expansion of clans, tribes, and confederacies into the “empty frontier.” This makes more sense of the reality that ancient DNA is witness to quick rapid disruptions, and later equilibration (perhaps as residual hunter-gatherers slowly become assimilated to the new society which is more self-confident in itself).
An implication of this model is that the chrysalis of later genetic and cultural variation was already preexistent rather early on. That is, if you looked at the ancient Near East, where several communities stumbled upon agriculture, perhaps in concert, you will see in these the “womb of nations.” The idea struck me as crazy when the blogger Dienekes Pontikos presented it in the late aughts based on patterns in admixture analyses. It strikes me as far less crazy after half a decade of ancient DNA. Now in the comments David points me to an abstract at SMBE which shows this all coming to a head:
The shift from hunter-gathering to food production, the so-called Neolithic Revolution, profoundly changed human societies. Whilst much is known about the mode of spread of people and domesticates into Europe during the Neolithic period, the origin of this cultural package in the Ancient Near East and Anatolia is poorly understood. By sequencing the whole genome (1.39x) of an early Neolithic woman from Ganj Dareh, in the Zagros Mountains of Iran, we show that the eastern part of the Ancient Near East was inhabited by a population genetically most similar to hunter-gatherers from the Caucasus but distinct from the Neolithic Anatolian people who later brought food production into Europe. Despite their key role in developing the Neolithic package, the inhabitants of Ganj Dareh made little direct genetic contribution to modern European populations, suggesting they were somewhat isolated from other populations in this region. Their high frequency of short runs of homozygosity, comparable to other early Neolithic farmers, suggests that they overwintered the Last Glacial Maximum in a climatically favourable area, where they may have received a genetic contribution from a population basal to modern Eurasians. Thus, the Neolithic package was developed by at least two genetically-distinct groups which coexisted next to each other, implying a degree of cultural yet little genetic exchange among them.
As I’ve said before, the the hunter-gatherers of the Caucasus share a lot of drift with South Indians. I’m betting that the woman from Ganj Dareh is part of the root population of what later became the dominant contributor to “Ancestral North Indians,” as well as the major vector of “Basal Eurasian” into the Yamnaya people.
Addendum: This site is very close to ancient Elam. This nation has been very speculatively associated with Dravidian languages. The Copper Age commercial ties with the Indus Valley Civilization in the Persian Gulf may be less surprising if many of these routes dated back to the early Neolithic expansion.
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