The spread of herds and horses into the Altai: How livestock and dairying drove social complexity in Mongolia.

The initial movement of herders and livestock into the eastern steppe is of great interest, as this region has long been home to pastoralist groups. Due to a paucity of faunal remains, however, it has been difficult to discern the timing of the adoption of domesticated ruminants and horses into the region, though recent research on ancient dairying has started to shed new light on this history. Here we present proteomic evidence for shifts in dairy consumption in the Altai Mountains, drawing on evidence from sites dating from the Early Bronze to the Late Iron Age. We compare these finds with evidence for the rise of social complexity in western Mongolia, as reflected in material remains signaling population growth, the establishment of structured cemeteries, and the erection of large monuments. Our results suggest that the subsistence basis for the development of complex societies began at the dawn of the Bronze Age, with the adoption of ruminant livestock. Investments in pastoralism intensified over time, enabling a food production system that sustained growing populations. While pronounced social changes and monumental constructions occurred in tandem with the first evidence for horse dairying, ~1350 cal BCE, these shifts were fueled by a long-term economic dependence on ruminant livestock. Therefore, the spread into the Mongolian Altai of herds, and then horses, resulted in immediate dietary changes, with subsequent social and demographic transformations occurring later.

Strong genetic admixture in the Altai at the Middle Bronze Age revealed by uniparental and ancestry informative markers.

The Altai Mountains have been a long-term boundary zone between the Eurasian Steppe populations and South and East Asian populations. To disentangle some of the historical population movements in this area, 14 ancient human specimens excavated in the westernmost part of the Mongolian Altai were studied. Thirteen of them were dated from the Middle to the End of the Bronze Age and one of them to the Eneolithic period. The environmental conditions encountered in this region led to the good preservation of DNA in the human remains. Therefore, a multi-markers approach was adopted for the genetic analysis of identity, ancestry and phenotype markers. Mitochondrial DNA analyses revealed that the ancient Altaians studied carried both Western (H, U, T) and Eastern (A, C, D) Eurasian lineages. In the same way, the patrilineal gene pool revealed the presence of different haplogroups (Q1a2a1-L54, R1a1a1b2-Z93 and C), probably marking different origins for the male paternal lineages. To go further in the search of the origin of these ancient specimens, phenotypical characters (i.e. hair and eye color) were determined. For this purpose, we adapted the HIrisPlex assay recently described to MALDI-TOF mass spectrometry. In addition, some ancestry informative markers were analyzed with this assay. The results revealed mixed phenotypes among this group confirming the probable admixed ancestry of the studied Altaian population at the Middle Bronze Age. The good results obtained from ancient DNA samples suggest that this approach might be relevant for forensic casework too.