Genetic origins of Minoans and Mycenaeans and their continuity into modern Greeks

mycenaean-minoan

A new article has appeared in Nature, Genetic origins of the Minoans and Mycenaeans, by Lazaridis et al. (2017), referenced by Science.

Abstract:

The origins of the Bronze Age Minoan and Mycenaean cultures have puzzled archaeologists for more than a century. We have assembled genome-wide data from 19 ancient individuals, including Minoans from Crete, Mycenaeans from mainland Greece, and their eastern neighbours from southwestern Anatolia. Here we show that Minoans and Mycenaeans were genetically similar, having at least three-quarters of their ancestry from the first Neolithic farmers of western Anatolia and the Aegean, and most of the remainder from ancient populations related to those of the Caucasus3 and Iran. However, the Mycenaeans differed from Minoans in deriving additional ancestry from an ultimate source related to the hunter–gatherers of eastern Europe and Siberia, introduced via a proximal source related to the inhabitants of either the Eurasian steppe or Armenia. Modern Greeks resemble the Mycenaeans, but with some additional dilution of the Early Neolithic ancestry. Our results support the idea of continuity but not isolation in the history of populations of the Aegean, before and after the time of its earliest civilizations.

Samples are scarce, and there is only one Y-DNA haplogroup of Mycenaeans, J2a1 (in Galatas Apatheia, ca. 1700-1200), which shows continuity of haplogroups from Minoan samples, so it does not clarify the potential demic diffusion of Proto-Greeks marked by R1b subclades.

Regarding admixture analyses, it is explicitly or implicitly (according to the press release) stated that:

  • There is continuity between Mycenaeans and living people, so that the major components of the Greeks’ ancestry was in place already in the Bronze Age, after the migration of the earliest farmers from Anatolia.
  • Anatolians may have been the source of “eastern” Caucasian ancestry in Mycenaeans, and maybe of early Indo-European languages (i.e. earlier than Proto-Greek) in the region.
  • The “northern” steppe population (speaking a Late Indo-European dialect, then) had arrived only in mainland Greece, with a 13-18% admixture, by the time studied.
  • Samples before the Final Neolithic (ca. 4100 BC) do not possess either type of ancestry, suggesting that the admixture detected occurred during the fourth to second millennium BC.
  • Admixture from Levantine or African influence (i.e. Egyptian or Phoenician colonists) cannot be supported with admixture.

All in all, there is some new interesting information, and among them the possibility of obtaining ancient DNA from arid regions, which is promising for future developments in the field.

EDIT (20/8/2017): The article received widespread media attention, and two blog posts were linked to by the main author in his Twitter account: Who are you calling Mycenaean?, and On genetics and the Aegean Bronze Age. Apart from the obviously wrong reductio ad Hitlerum that pops up in any discussion on Indo-Europeans or genetics (even I do it regarding fans of admixture analysis), I don’t know why these created so much fuss (and hate) among geneticists. There seems to be a war brewing between Archaeology and Genetics.

Razib Khan writes The Revolution Which Came To Archaeology Without Archaeologists?, and I guess this is how many people feel in the field, but if they had studied some minimal archaeology of the samples they are studying they would know that their conclusions would come as no surprise, in any case. They can solve old archaeological questions, and they can help create new hypothesis. That’s it. Regarding the study Mr. Khan believes did come as a surprise to archaeologists, that on Bell Beakers, I would like to remind him of the predictions Volker Heyd did about genetics already in 2007, based only on Archaeology.

Related:

Featured map: samples studied, from the article.

Another nail in the coffin for the Anatolian hypothesis: continuity and isolation in the Caucasus during the Neolithic and Calcholithic, in mtDNA samples

caucasus-armenia

A new paper appeared on Current Biology, by Margaryan et al. (including Morten E. Allentoft): Eight Millennia of Matrilineal Genetic Continuity in the South Caucasus.

Among its conclusions:

The plot clearly shows the clustering of the ancient group together with the modern European, Armenian, and Caucasian populations. We observe none of the typical East Eurasian mtDNA lineages (A, C, D, F, G, and M) among the ancient individuals, and only one individual with haplogroup D is present in the modern Armenian maternal gene pool (Artsakh). As such, the archaeologically and historically attested migrations of Central Asian groups (e.g., Turks and Mongols) into the South Caucasus [14, 15] do not seem to have had a major contribution in the maternal gene pool of Armenians. Both geographic (mountainous area) and cultural (Indo-European-speaking Christians and Turkic-speaking Muslims) factors could have served as barriers for genetic contacts between Armenians and Muslim invaders in the 11th–14th centuries CE. The same pattern was observed using Y chromosome markers in geographically diverse Armenian groups.

Also, regarding the potential Indo-European migration into the area:

It appears that during the last eight millennia, there were no major genetic turnovers in the female gene pool in the South Caucasus, despite multiple well-documented cultural changes in the region [27, 28]. This is in contrast to the dramatic shifts of mtDNA lineages occurring in Central Europe during the same time period, which suggests either a different mode of cultural change in the two regions or that the genetic turnovers simply occurred later in Europe compared to the South Caucasus. More data from earlier Mesolithic cultures in the South Caucasus are needed to clarify this. During the highly dynamic Bronze Age and Iron Age periods, with the formation of complex societies and the emergence of distinctive cultures such as Kura-Araxes, Trialeti-Vanadsor, Sevan-Artsakh, Karmir-Berd, Karmir-Vank, Lchashen-Metsamor, and Urartian, we cannot document any changes in the female gene pool. This supports a cultural diffusion model in the South Caucasus, unless the demographic changes were heavily male biased, as was most likely the case in Europe during the Bronze Age migrations [29, 30]. However, genome-wide data from the few Bronze Age individuals published so far from the South Caucasus also support a continuity scenario [26]. Another possibility is that any gene flow into the South Caucasus occurred from groups with a very similar genetic composition, facilitating only subtle genetic changes that are not detectable with the current datasets.

I would obviously support the latter possibility, a demic diffusion that can be shown by precise subclade and admixture analyses, because cultural diffusion is quite difficult to justify in any ancient setting. Since it is most likely south-eastern European R1b-Z2103 lineages (or R1b-M269, if resurged during the proto-language transition in the Balkans) the original marker of Palaeo-Balkan speakers, that is what one should be looking for in Y-DNA investigation in the area. Since migrations were probably male-biased, it is not likely that mtDNA was much affected. But, especially during the Iron Age, a change should also be seen, marked by the appearance of (recent) U subclades.

Related:

The Aryan migration debate, the Out of India models, and the modern “indigenous Indo-Aryan” sectarianism

On the origin of R1a and R1b subclades in Greece

News of the article seen first in Eurogenes (you can see the specific samples there).

Featured image is from the article.