Austro-Asiatic tribes of Northeast India provide hitherto missing genetic link between South and Southeast Asia

Abstract

Northeast India, the only region which currently forms a land bridge between the Indian subcontinent and Southeast Asia, has been proposed as an important corridor for the initial peopling of East Asia. Given that the Austro-Asiatic linguistic family is considered to be the oldest and spoken by certain tribes in India, Northeast India and entire Southeast Asia, we expect that populations of this family from Northeast India should provide the signatures of genetic link between Indian and Southeast Asian populations. In order to test this hypothesis, we analyzed mtDNA and Y-Chromosome SNP and STR data of the eight groups of the Austro-Asiatic Khasi from Northeast India and the neighboring Garo and compared with that of other relevant Asian populations. The results suggest that the Austro-Asiatic Khasi tribes of Northeast India represent a genetic continuity between the populations of South and Southeast Asia, thereby advocating that northeast India could have been a major corridor for the movement of populations from India to East/Southeast Asia.

Figure 1. Map of Meghlaya showing the core areas of geographic distribution of the Khasi and Garo populations.

Figure 2. Rooted maximum-parsimony tree of Y-chromosome haplogroups defined by binary markers along with their frequency in Nine Meghalayan Populations.

Figure 3. Plot on the first two dimensions derived from the multidimensional scaling of the pairwise F_ST distances of the populations based on Y-haplogroups.

Reference to comparative data is given at Table 5. SEA, Southeast Asian; AA, Austro-Asiatic; IE, Indo-European, TB, Tibeto-Burman; Khy, Khynriam; Lyn, Lyngngam; Wkhasi, War Khasi; Viet, Vietnamese;

Figure 4. Phylogenetic tree of new haplogroups based on full mtDNA along with the TMRCA and associated 95% Confidence Interval.

The samples names are on the tip of the haplogroups. The comparative data, for which sample names are written in capital letters, are from Kong et al. , Thangaraj et al. , Sun et al. and Palanichamy et al. .

Figure 5. Tree Drawn from a Median-Joining Network of mtDNA Haplogroups Observed in Nine Meghalayan Populations.

The haplogroups box in yellow colour are either new or redefined haplogroups.

Figure 6. Plot on the first two dimensions derived from the multidimensional scaling of the pairwise F_ST distances of the populations based on mtDNA haplogroups.

Reference to comparative data is given at Table 6. SEA, Southeast Asian; AA, Austro-Asiatic; IE, Indo-European; TB, Tibeto-Burman; Wk, WarKhasi; Ch, Chong;