The Yamnaya Steppe Herders from Russia Feb 22, 2021 0:49:18 GMT
Post by Admin on Feb 22, 2021 0:49:18 GMT
After the last glacial period, at the end of the 10th and the beginning of the 9th millennium BC, vast areas in the Eastern Baltic, Finland, and northern parts of Russia were populated relatively quickly by HG groups (42–44). Flint originating from several places in the Eastern Baltic and the European part of Russia and the similarities in lithic and bone technologies and artifacts suggest the existence of extensive social networks in the forest belt of Eastern and Northern Europe after it was populated (43, 45, 46). This has led to the hypothesis that the descendants of Final Paleolithic HG from eastern Poland to the central areas of European Russia took part in the process (8, 47) and remained connected to their origin, creating a somewhat stretched social network (4). However, these connections ceased after a few centuries, as can be witnessed from the production of stone tools from mostly local materials, and new geographically smaller social units appeared in the middle of the 9th millennium BCE (4). aDNA studies of this area have included Mesolithic individuals that are from the 8th millennium BC or younger and reveal two genetic groups: WHG in the Eastern Baltic and EHG in northwestern Russia (14–17, 27, 34). However, no human genomes from the settlement period have been published so far, leaving the genetic ancestry/ancestries of the settlers up for discussion. The individual PES001 from around 10,700 cal BCE presented here with 5× coverage provides evidence for EHG ancestry in northwestern Russia close to the time it was populated. This, in turn, raises the question—hopefully answered by future studies—of the ancestry of the first people of the Eastern Baltic: Did they have EHG ancestry, as suggested by the shared social network of the two areas at the time of settlement, and an influx of WHG ancestry people later, not accompanied by a change in archaeological material, or did WHG ancestry people live in the Eastern Baltic from the beginning, representing a case of groups with different ancestry sharing a similar culture?
The formation of Fatyanovo Culture is one of the main factors that affected the population, culture, and lifestyle of the previously hunter/fisher-gatherer culture of the Eastern European forest belt. The Fatyanovo Culture people were the first farmers in the area, and the arrival of the culture has been associated with migration (21, 24). This is supported by our results as the Stone Age HG and the Bronze Age Fatyanovo individuals are genetically clearly distinguishable. The sample size of our HG is low, but the three individuals form a genetically homogenous group with previously reported EHG individuals (14, 16), and the newly reported PES001 is the highest-coverage whole-genome sequenced EHG individual so far, providing a valuable resource for future studies. What is more, the Fatyanovo Culture individuals (similarly to other CWC people) have not only mostly Steppe ancestry but also some EF ancestry that was not present in the area before and thus excludes the northward migration of Yamnaya Culture people with only Steppe ancestry as the source of Fatyanovo Culture population. The strongest connections for Fatyanovo Culture in archaeological material can be seen with the Middle Dnieper Culture (23, 48) spread in present-day Belarus and Ukraine (49, 50). The territory of what is now Ukraine is where the most eastern individuals with European EF ancestry and the most western Yamnaya Culture individuals are from based on published genomic data (13, 51) (Fig. 1 and data S1). Furthermore, archaeological finds show that LBK reached western Ukraine around 5300 BCE (52), and the Yamnaya complex (burial mounds) arrived in southeastern Europe around 3000 BCE and spread further as far as Romania, Bulgaria, Serbia, and Hungary (53). This is in accordance with our genetic results as the two populations that proved to be plausible mixture sources for Fatyanovo, with the other source being either of the two Russian Yamnaya groups (Kalmykia or Samara), were Globular Amphora that includes individuals from Ukraine and Poland, and Trypillia that is composed of individuals from Ukraine. These findings suggest present-day Ukraine as the possible origin of the migration leading to the formation of the Fatyanovo Culture and of the Corded Ware cultures in general.
The exact timing of and processes involved in the emergence of the Fatyanovo Culture in European Russia and the local processes following it have also remained unclear. Until recently, the Fatyanovo Culture was thought to have developed later than other CWC groups and over a longer period of time (21, 23). However, radiocarbon dates published last year (24), in combination with the 25 new dates presented here and the estimate for Yamnaya and EF admixture ~300 to 500 years before the Fatyanovo individuals of this study lived, point toward a fast process, similar in time to CWC people reaching the Eastern Baltic and southern Fennoscandia (54–56). The archaeological cultures are clearly differentiated between the areas. What is more, it has been suggested that the Fatyanovo Culture people admixed with the local Volosovo Culture HG after their arrival in European Russia (21, 57, 58). Our results do not support this as they do not reveal more HG ancestry in the Fatyanovo people compared to two other CWC groups; the three groups are shown to be similar by nonrejected one-way qpAdm models, and correlating radiocarbon dates with PC values or qpAdm ancestry proportions reveals no change in ancestry proportions of the Fatyanovo people during the period covered by our samples (2900 to 2050 BCE).
Last, allele frequency changes in western Russia and the Eastern Baltic revealed similar patterns in both areas: The frequencies of alleles in the MCM6 and FADS1-2 genes, which have been hypothesized to have changed due to dietary shifts from the Neolithic onward (16, 29, 59), change significantly during the Bronze Age, although the first signals of change can be seen already from the Neolithic. In accordance with a recent publication on lactase persistence (60), we find a low frequency of the rs4988235A allele in the initial Steppe ancestry samples [90% CI, 0 to 2.7% in (60), 0 to 33.8% in this study]. This suggests that the factors affecting these allele frequency shifts over time were complex and may have involved several environmental factors and genetic forces, as has already been suggested previously (14, 16, 18, 28, 29, 60, 61).