09 marzo 2012


Etruscan historical genetics done right

Most of you know that I believe there are serious problems with much of contemporary historical population genetics. Grand unfounded narratives, and scientists who lack requisite historical knowledge, litter the field. But, narrow, precise and crystal clear studies do emerge now and then. This is a case in point, Mitochondrial DNA Variation of Modern Tuscans Supports the Near Eastern Origin of Etruscans:

Interpopulation comparisons reveal that the modern population of Murlo, a small town of Etruscan origin, is characterized by an unusually high frequency (17.5%) of Near Eastern mtDNA haplogroups. Each of these haplogroups is represented by different haplotypes, thus dismissing the possibility that the genetic allocation of the Murlo people is due to drift. Other Tuscan populations do not show the same striking feature; however, overall, 5% of mtDNA haplotypes in Tuscany are shared exclusively between Tuscans and Near Easterners and occupy terminal positions in the phylogeny. These findings support a direct and rather recent genetic input from the Near East.

Sometimes history can be extremely well illuminated by simple genetic studies. This is one such case. The origins of the Etruscans are (were?) “mysterious.” Some would hold that they are indigenous to the Italian peninsula, while others promote a more exotic provenance. Here is Herodotus, the father of lies:

The customs of the Lydians are like those of the Greeks, except that they make prostitutes of their female children. They were the first men whom we know who coined and used gold and silver currency; and they were the first to sell by retail. And, according to what they themselves say, the games now in use among them and the Greeks were invented by the Lydians: these, they say, were invented among them at the time when they colonized Tyrrhenia….

Tyrrehnia is Etruria, modern Tuscany. When I first encountered the “Lydian hypothesis,” I was rather skeptical. After all, how plausible is it that Anatolians around ~1000 BCE set off and colonized the northwest coast of the Italian peninsula? It seemed to me that a more likely possibility was that the Etruscans emerged from the indigenous non-Indo-European substratum of Italy, and that any coincidences with Anatolian cultural forms were happenstance or due to diffusion. This is a common model in archeology, people do not move, cultural elements do, and parallelism is a common tendency. An anti-migration bias probably is a backlash against the assumption in the early half of the 20th century that entire populations took flight or were displaced in the ancient world. The British imagined themselves descended from Anglo-Saxon Germans, not the Celts they conquered. The Arab speaking peoples of course were descended from Arabs who conquered the indigneous people of the Middle East, who dissipated over time. And so on. But the reality is clealry very different, a general trend seems to be that cultural elites can have great impact and transform the mores of a subject population, and that this was more common than wholesale replacement. Nevertheless, there are counter examples, and the Etruscans seem to be one. It is particularly instructive that female genetic data, mitochondrial haplotypes, were used to point to their likely exogenous origin, because colonizing groups usually take local wives. That the Anatolians brought their women suggests that this was a folk wandering of massive proportions, more like the British settlement of the eastern North American seaboard than the Spanish colonization of Latin America. According to Oxford classicist Robin Lane Fox the Greek colonial expeditions, which barely post-dated the putative Anatolian emigration, were characterized by a very strong male bias in sex ratios. It seems that the Greek colonial policy was driven by overpopulation and political troubles at home, disruptive were men simply sent off overseas. If Etruscan men and women journeyed across the Mediterranean that suggests a wholesale transplation, not just the emigration of a slice of the population which needed to be got rid of.

In any case, I do find it interesting that the Romans concocted a tale of their Trojan origins, because Troy is located to the north and west of the ancient Lydian homeland. Surely coincidence, but a deliciously amusing one nonetheless.

Technical Notes: The diversity of haplotypes from the Near East suggests that large number of immigrants who represented the full range of Near Eastern diversity. If only a small group arrived but reproduced prolifically founder effect would blow up the inevitable sampling error from the source population. The Etruscans would have been a more distorted slice of the Middle Eastern mtDNA landscape. Similarly, if the peculiarity was due to genetic drift pushing up a the frequency of an exotic allele, then that would have extinguished most of the variation and resulted in one lineage being predominant. The diversity tends to argue against this.

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