I'm hoping like hell that the samples from this thesis eventually get the same treatment as those from Haak et al. 2015.
Summary: This dissertation presents the first genetic study of prehistoric populations in the Pontic-Caspian steppe from the Upper Thracian Plain to the Volga. Hypervariable region I (HVR I) and 30 short sections of the coding region containing 32 clade- determining polymorphisms on the mitochondrial DNA, as well as 20 putatively naturally selected autosomal SNPs and a sex-determining locus were analysed using a combination of multiplex PCR and 454 sequencing. Data analysis was performed on the HVR I of 65 of the 180 Eneolithic and Bronze Age samples. (Partial) genotypes were generated from 61 individuals. Published ancient DNA data from Central and Eastern Europe and Central Asia, as well as modern DNA sequences were consulted for comparison.
The genetic data support the inference that early Neolithic farmers from Southeast Europe were involved in establishing pastoralism in the steppes by demic diffusion. The consistently low values of the FST-statistic (the range includes zero) between the Yamnaya Culture of the steppe and a succession of Neolithic cultures in Central Europe indicate continuous or recurrent contacts between the two regions. Between the Yamnaya Culture and its successor, the Catacomb Culture, the incidence of haplogroup U4, which is at high frequency in hunter-gatherer populations of Neolithic Scandinavia and Mesolithic Northwest Russia, rises from approximately 5 % to above 30 %. It is possible that immigrants from Eastern Baltic hunter-gatherer refugia were involved in the genesis of the Catacomb Culture.
The low FST values between the prehistoric steppe populations and the modern populations of Central and Eastern Europe indicate genetic continuity. This is supported by the nuclear genotype frequencies. According to current knowledge the modern European gene pool can be explained by three roots: indigenous Mesolithic hunter-gatherers, early farmers from the Near East, and an ancient North Eurasian component with an Upper Palaeolithic origin. Maybe the third ancestry component was introduced into the late Neolithic European genome by the North Pontic population.
Source: Wilde, Sandra, Populationsgenetik kupfer- und bronzezeitlicher Bevölkerungen der osteuropäischen Steppe, 2014, Dissertation