(CN) — A rapidly diversifying gene pool led to a decline of sedentary groups in the long-lasting Bronze Age and gave rise to the Scythian nomad tribes of the Iron Age, new research suggests.
The study was published Friday in the journal Science Advances and is based on research by an international team of geneticists, anthropologists and archaeologists led by scientists from Germany’s Max Planck Institute for the Science of Human History.
The Scythians were a blend of many horse-warrior nomadic tribes that inhabited the Eurasian Steppe during the first millennium BCE. Because there are no firsthand written records from the era, little is known about the origins of or relations among the different Scythian cultures.
To address these questions, the research team, headed by Guido Alberto Gnecchi Ruscone from the Max Planck Institute’s Department of Archaeogenetics, produced genome data from the remains of 111 ancient bodies gathered from 39 archaeological sites across the Central Asian Steppe.
Researchers discovered major so-called admixture events in the late Bronze Age that formed the genetic foundation for two main Iron Age gene pools that emerged around the Altai and Urals regions.
The demise of the populations there was mirrored by genetic turnovers, the study found, and was linked to the spread of the eastern nomad empires in the first centuries CE.
“Compared to the high genetic heterogeneity of the past, the homogenization of the present-day Kazakhs gene pool is notable, likely a result of 400 years of strict exogamous social rules,” the study states.
Following the relatively homogenous ancestry of late Bronze Age herders, influxes of people from the east, west and south at the turn of the first millennium BCE formed new mixed gene pools, the researchers found.
The study sheds light on the illusive history of the Scythians in the researchers’ identification of the 111 ancient genomes from the Central Asian Steppe.
“The study goes even further, identifying at least two main sources of origin for the nomadic Iron Age groups,” according to a press release announcing the findings.
An eastern DNA source likely came from people in the Altai Mountains who spread west and south during the Iron Age, intermixing as they went.
Genetic results match with the timing and locations found in the archeological record and hint at an expansion of populations from the Altai area, where the earliest Scythian burials are found. The intermixing connected various renowned cultures such as the Saka, the Tasmola and the Pazryk found in southern, central and eastern Kazakhstan, respectively, researchers found.
“Surprisingly, the groups located in the western Ural Mountains descend from a second separate, but simultaneous source,” the press release states. “Contrary to the eastern case, the western gene pool, characteristic of the early Sauromatian-Sarmatian cultures, remained largely consistent through the westward spread of the Sarmatian cultures from the Urals into the Pontic-Caspian steppe.”
Ruscone, the researcher who headed the study, was not immediately available for comment Friday.
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