FROM THE SARMATIANS TO THE PROTO-BULGARIANS: PALEOGENETIC PERSPECTIVES ON THE POPULATION CHANGES IN THE EURASIAN STEPPE AND THE BALKANS.

We investigate paleogenomic history of the Sarmatians, Iranianspeaking nomads who dominated the Eurasian steppe in late antiquity. Analyzing ancient DNA from 195 individuals, we explore Sarmatian population dynamics, admixture patterns, and their connections to Scythians, Huns, early Bulgarians, and Balkan groups during the Migration Period. Our results reveal that Sarmatians originated from the Southern Urals, expanded westward, displacing Scythians, and formed two groups in the Hungarian plain. In the 4th -- 5th century, Sarmatians from Hungarian Plain experienced gene flow from Baltic and Slavic sources. Tisza Sarmatians exhibited a distinct Illyrian-Italic signal and weaker Caspian signal compared to Danubian Sarmatians, with a larger proto-Slavic and significant Illyrian-Italian component. Conversely, Danubian Sarmatians had larger Siberian and Central Asian components. Demographic shifts leading to Sarmatian and Hun emergence in the Hungarian plain and Scythian decline in the Black Sea region were likely influenced by military and political pressures first from The Xiongnu and later from Imperial China in Central Asia. We identify a genetic component present in early Bulgarians but not in most other Slavic and Balkan individuals. Additionally, we detect a weak but distinct signal from the Kangju, representing a possible late European migration into Asia. While early Bulgarian and Balkan genomes mostly mirrored Tisza Sarmatians, two North Caucasus steppe genomes from the 8th to 10th century demonstrated a historical connection. [ABSTRACT FROM AUTHOR]