The genetic admixture and assimilation of Ahom: a historic migrant from Thailand to India

The Northeastern region of India is considered a gateway for modern humans' dispersal throughout Asia. This region is a mixture of various ethnic and indigenous populations amalgamating multiple ancestries. One reason for such amalgamation is that, South Asia experienced multiple historic migrations from various parts of the world. A few examples explored genetically are Jews, Parsis and Siddis. Ahom is a dynasty that historically migrated to India during the 12th century. However, this putative migration has not been studied genetically at high resolution. Therefore, to validate this historical evidence, we genotyped autosomal data of the Modern Ahom population residing in seven sister states of India. Principal Component and Admixture analyses haave suggested a substantial admixture of the Ahom population with the local Tibeto-Burman populations. Moreover, the haplotype-based analysis has linked these Ahom individuals mainly with the Kusunda (a language isolated from Nepal) and Khasi (an Austroasiatic population of Meghalaya). Such unexpected presence of widespread population affinities suggests that Ahom mixed and assimilated a wide variety of Trans-Himalayan populations inhabiting this region after the migration. In summary, we observed a significant deviation of Ahom from their ancestral homeland (Thailand) and extensive admixture and assimilation with the local South Asian populations.