This open access paper on the genetic prehistory of the Great Hungarian Plain is full of surprises. Here are a few of my observations:
- Four of the genomes from a Neolithic farming context produced two Y-haplogroups previously identified in Mesolithic European hunter-gatherers (I2a and C6), and one of the samples (KO1) could probably pass for a Mesolithic hunter-gatherer overall, suggesting that males of hunter-gatherer origin played a major role in early European Neolithic societies. But what's happened to the C6 since then?
- The two Bronze Age genomes, BR1 and BR2, look very present-day French, and probably western French at that, in both the Principal Component and Admixture analyses. Indeed, they clearly show a northern influence relative to all of the Neolithic farmers and the Iron Age IR1. And yet, BR2 belongs to Y-haplogroup J2a1, which is generally seen as a Near Eastern marker.
- IR1 is described as a pre-Scythian genome with both East Eurasian and North Caucasian affinities
(it's not clear in the paper whether it belongs to Y-haplogroup N and mtDNA G2a1, or vice versa, although either way works in this context). However, it also shows significant Northern European-like ancestry, and is even inferred to have fair hair, which makes me think that its eastern shift might be in large part due to Eastern Hunter-Gatherer (EHG) or Yamnaya-related admixture, which is now pervasive across Northern Europe (see here).
- Many people, including myself nowadays, see the Carpathian Basin as potentially a major staging point for the expansion of Y-chromosome haplogroup R1b into Central and Western Europe during the Bronze Age. And yet, it's again missing from the line-up.
- The T allele at SNP rs4988235, associated with lactase persistence into adulthood in Europeans, is only present among the two most recent genomes: BR2 and IR1. This suggests that selection for this allele, which now reaches frequencies of well over 50% in much of Europe, post dates not only the Neolithic but also the early Indo-European period, and was possibly most intense during the metal ages.
- Some of the Neolithic samples are clearly shifted towards the Bedouins (Bed) in Figure 2, relative to Oetzi the Iceman, a Copper Age genome from the Tyrolean Alps, which is generally considered to be typical of European Neolithic farmers (see below). So perhaps further sampling of Neolithic remains from southern Europe, in particular the southern Balkans, might reveal early farmers who actually cluster with Near Eastern populations, rather than Europeans?
- The authors found a sweetspot for extracting ancient DNA from humans: "the petrous portion of the temporal bone, the densest bone in the mammalian body". The amount of endogenous DNA salvaged from this part of the skull exceeds those from other bones by up to 183-fold. This is obviously great news, and probably means we can expect many more ancient genomes to be published in the near future.
Gamba, C. et al. Genome flux and stasis in a five millennium transect of European prehistory. Nat. Commun. 5:5257 doi:10.1038/ncomms6257 (2014).
First I1-M253 from prehistoric Europe
Genetic continuity and shifts across the metal ages in the Carpathian Basin: analysis of ancient Hungarian genomes CO1, BR1 and IR1