Abstract: Peloponnese has been one of the cradles of the Classical European civilization and an important contributor to the ancient European history. It has also been the subject of a controversy about the ancestry of its population. In a theory hotly debated by scholars for over 170 years, the German historian Jacob Philipp Fallmerayer proposed that the medieval Peloponneseans were totally extinguished by Slavic and Avar invaders and replaced by Slavic settlers during the 6th century CE. Here we use 2.5 million single-nucleotide polymorphisms to investigate the genetic structure of Peloponnesean populations in a sample of 241 individuals originating from all districts of the peninsula and to examine predictions of the theory of replacement of the medieval Peloponneseans by Slavs. We find considerable heterogeneity of Peloponnesean populations exemplified by genetically distinct subpopulations and by gene flow gradients within Peloponnese. By principal component analysis (PCA) and ADMIXTURE analysis the Peloponneseans are clearly distinguishable from the populations of the Slavic homeland and are very similar to Sicilians and Italians. Using a novel method of quantitative analysis of ADMIXTURE output we find that the Slavic ancestry of Peloponnesean subpopulations ranges from 0.2 to 14.4%. Subpopulations considered by Fallmerayer to be Slavic tribes or to have Near Eastern origin, have no significant ancestry of either. This study rejects the theory of extinction of medieval Peloponneseans and illustrates how genetics can clarify important aspects of the history of a human population.Stamatoyannopoulos et al., Genetics of the peloponnesean populations and the theory of extinction of the medieval peloponnesean Greeks, European Journal of Human Genetics advance online publication 8 March 2017; doi: 10.1038/ejhg.2017.18
Saturday, March 18, 2017
Greek confirmation bias
A new paper at the EJHG claims that Slavic admixture in Peloponnesean Greeks averages a few per cent at best (see abstract below). However, I'd say the authors are making two potentially erroneous assumptions: 1) that Slavic invaders arrived in Greece straight from the Slavic homeland, probably located somewhere in East Central or Eastern Europe, and 2) modern-day Northern Slavs (Belarusians, Poles, Russians and Ukrainians) are accurate proxies for these ancient invaders. Keep in mind that when the Slavs moved into the Balkans during the Early Middle Ages, they routinely absorbed the natives into their bands as free men and women (excellent paper on the topic here). So their numbers swelled thanks to this more southerly, local input, and, at the same time, their genetic structure shifted in a big way, probably from more or less Northern Slavic to modern-day Southern Slavic. Indeed, it's likely that by the time they arrived in the Peloponnese, they were less like this and more like this, or even this. So was Fallmerayer correct when he theorized that the Peloponnese was totally re-populated by Slavs during the Medieval period? Probably not, but the population shift may still have been profound, and totaling much more than a few per cent. I can't wait for more ancient DNA from Greece and Italy, especially from the Bronze and Iron Ages. Based on my experiences with many Greeks and Italians, it's sure to be a big eye opener for them, and a beautiful thing.