The Yamnaya Steppe Herders from Russia

Discussion
The Carpathian Basin was inhabited by the Baden cultures’ population at the end of the Copper Age, and their genetic composition was represented by an early farmer and a slightly increased HG genetic component, compared to the previous Neolithic populations of the region6. Here we demonstrated that in the early phase of this culture, a group of Western European origin appeared in Transdanubia, diversifying what we knew about the region’s Late Copper Age substrate up to now.

The Carpathian Basin experienced the influx of steppe-related genetic ancestry at the dawn of the Bronze Age5,8, and this transformation was already detectable at Balatonkeresztúr-Réti-dűlő site as well, where we could examine multiple populations. The earliest Bronze Age horizon Bk-I (representative of the Somogyvár-Vinkovci culture) shows similarities to Poland Southeast BBC associated population with high steppe ancestry that was replaced by the Kisapostag culture associated Bk-II around the 23-22th century BCE, while at least some sort of genetic ancestry of Bk-I in this population can not be excluded. According to our results, the Bk-II population had outstandingly high HG genetic ancestry levels, compared to other Bronze Age groups of the region, which can be traced back to today’s Ukraine, Belarus, Moldavia or Romania, pointing to a long standing previously unsampled population with dominant HG ancestry. Calculated admixture dates10 suggest the presence of a genetically pure or at least highly HG specific population in Eastern Europe as late as the end of the Copper Age. Part of this group subsequently admixed with populations of mainly steppe (likely Poland Southeast BBC) and early farmer (most likely a Globular Amphora culture related) ancestry during their westward migration on a Northern route, leaving genetic traces in Corded Ware culture, BBC, and other Bronze Age populations. The paternal lineage of BK-II was likely linked to the farmer component, as I2a-M223 (upstream to I2a-L1229) was a frequent paternal lineage among Globular Amphora culture and related populations. Looking for the possible source areas of the Kisapostag culture, a number of archaeological theories need to be considered. The pottery decoration technique originated either from Corded Ware in the Middle Dnieper region (Ukraine), epi-Corded Ware groups (northern Carpathians), e.g. Chłopice-Veselé or Nitra groups (Slovakia), the latter two is also supported by inhumation practises31–36. However, connections with the Litzenkeramik or Guntramsdorf-Drassburg group (eastern Austria, Slovenia, western Croatia) were also raised37,38. Pottery forms were connected to local development of communities with eastern (Makó–Kosihy–Čaka) or southern (Somogyvár–Vinkovci) origins, too39. BBC influence was also mentioned based on connections of pottery and craniometry data (so called Glockenbecher or brachycran skull type40–42). The results of this study fit best with the Middle Dnieper area origin of BK-II, especially when we consider individual I4110 from Dereivka I (Ukraine Eneolithic) as one of the earliest representatives of their genomic makeup.

Strontium isotope (87Sr/86Sr ratio) data, representing through nutrition the bioavailable Sr in the area where people lived in a certain age interval, shows local values for both sexes in both Bk-II and Bk-III. These results push back the timing of their arrival a few generations, meaning that local or southern impact of cultural traits and maybe even genetic admixtures likely occurred during this short period as well, which also could explain the culture’s archaeological heterogeneity.

The population of Bk-III was the direct descendant of Bk-II, forming not just cultural (Encrusted pottery) but also genetic continuity for at least ~500 years, even if the radiocarbon sequences allow a few decades of hiatus at the studied site. Continuous female-biased admixture with various groups occurred during this period according to our and previous genetic10 and archaeological31,43 evidence, diluting the BK-II genetic ancestry.

In both periods, the homogeneity of paternal lineages suggest a similar social organisation described in9,10 of a patrilocal residence system. However, strontium isotope data shows local values for both sexes, which along with similar genomic makeup of females and males suggest exogamy most probably between villages of the same population. Two pairs of half-sibling graves in the two periods may indicate polygamy, although remarriage for high female mortality is more plausible. Notably, almost none of the uniparental markers are identical even at the haplogroup level with individuals from the Croatian Encrusted Pottery culture Jagodnjak site, despite high similarities in cultural traits, social structure and genomic composition of the communities. This points to clan-like or patriarchal superfamily structure of Kisapostag and Encrusted Pottery groups. The relatively limited presence of female and children burials in both Bk-II and Bk-III periods may suggest distinctive treatment or another (here undiscovered) burial group for women and children at the same site. Although, in other Bronze Age cemeteries, e.g. Ordacsehi and Bonyhád in Hungary, males, females and children were buried close to each other, suggesting high variance of burial practises34,35,44.

While low genomic coverage did not allow fine SNP recovery, we did find evidence for malignant variants within all of our tested groups, and undoubtedly showed the presence of LHON and Jacob’s syndrome within Bk-II. Additionally, the disease panel we created can be extended and used in future studies, providing insight into past population health qualities.

Considering the unstructured age and kinship distribution in the mass grave Bk-III compared to Bk-II, the coetaneous death of eight people at least, the absence of traumatic or ritual events on bones, and non-cremated nature of the burial all signals a sudden tragic event in the Encrusted pottery period, most likely an epidemic, as first suggested based on the anthropological analyses45. Interestingly, comparative strontium isotope analyses on the first and third molar of the individuals in the BK-III mass grave indicate that subadult males - including a severely disabled individual (S15) with hip dysplasia - left their community for a while and then returned to their birthplace prior to their death, raising further questions for future studies on prehistoric lifeways and social organisations.