Open access at Nature Communications today: Large-scale recent expansion of European patrilineages shown by population resequencing by Batini et al.
It's a shame the authors failed to sample any Eastern European populations, but it's still a very useful effort which moves us in the right direction in an area of study that has floundered from the start, largely due to the widespread use of bikini STR haplotypes and faulty methodology. From the paper:
Here, we use targeted NGS of European and Middle Eastern populations to show that Europe was affected by a major continent-wide expansion in patrilineages that post-dates the Neolithic transition. Resequencing at high coverage of 3.7 Mb of MSY DNA, in each of 334 males comprising 17 population samples, defines an unbiased phylogeny containing 5,996 high-confidence single-nucleotide polymorphisms (SNPs). Dating indicates that three major lineages (I1, R1a and R1b), accounting for 64% of the sampled chromosomes, have very recent coalescent times, ranging between 3.5 and 7.3 KYA. In demographic reconstructions (17) a continuous swathe of 13/17 populations from the Balkans to the British and Irish Isles share similar histories featuring a minimum effective population size ~2.1–4.2 KYA, followed by expansion to the present. Together with other data on maternally inherited mtDNA (16, 18) and autosomal DNA (19), our results indicate a recent widespread male-specific phenomenon that may point to social selection, and refocuses interest on the social and population structure of Bronze Age Europe.Batini, C. et al. Large-scale recent expansion of European patrilineages shown by population resequencing. Nat. Commun. 6:7152 doi: 10.1038/ncomms8152 (2015).
The shapes of different clades within the tree (Fig. 1a) vary greatly. Haplogroups E1b-M35, G2a-L31, I2-P215, J2-M172, L-M11 and T-M70 contain long branches with deep-rooting nodes, whereas I1-M253, N1c-M178, R1a-M198 and R1b-M269 show much shallower genealogies.
The recent and rapid continent-wide demographic changes we observe suggest a remarkably widespread transition affecting paternal lineages. This picture is confirmed in an independent analysis of MSY diversity in the pooled HGDP CEPH panel European samples (16), and is compatible with current (n=98) ancient DNA data for MSY (Fig. 3; Supplementary Table 8), in which hgs R1a, R1b and I1 are absent or rare in sites dating before 5 KYA, whereas hgs G2a and I2 are prevalent.
The period 4–5 KYA (the Early Bronze Age) is characterized by rapid and widespread change, involving changes in burial practices that might signify an emphasis on individuals or kin groups, the spread of horse riding, and the emergence of elites and developments in weaponry (35). In principle male-driven social selection (36) associated with these changes could have led to rapid local increases in the frequencies of introgressing haplogroups (34), and subsequent spread, as has been suggested for Asia (37). However, cultures across Europe remain diverse during this period; clarifying the temporal and geographical pattern of the shift will rely heavily on additional ancient DNA data.
R1a1a from an Early Bronze Age warrior grave in Poland
Massive migration from the steppe is a source for Indo-European languages in Europe (Haak et al. 2015 preprint)