Presentation Abstract

Title: P16.085 - Population diversity and history of the Indian subcontinent: Uncovering the deeper mosaic of sub-structuring and the intricate network of dispersals
Keywords: population diversity; admixture; haplotype
Authors: A. Basu1, N. Sarkar Ray1, P. P. Majumder1,2;
1National Institute of BioMedical Genomics, Kalyani, India, 2Indian Statistical Institute, Kolkata, India.
Abstract: Past genomic studies have provided a broad picture of the peopling of the India: proposing a southern exit route through western coastline and migration from west and central Asia, through north-western corridor. We undertook a genome-wide study (Illumina 1M SNP chip) comprising 367 individuals, drawn from 20 ethnic groups of India representing all geographic regions, linguistic groups and social hierarchies, including hunter-gatherers from Andaman&Nicobar(A&N) Islands.
Our analysis corroborated with previous studies on the existence of deep rooted population structure in India, as evidenced by a high average pairwise FST ~0.04. The average pairwise FST was extremely high (>0.1) between A&N and the mainland Indian populations, indicating the high differentiation.
Unlike Europe, geography alone is a poor predictor of genetic diversity and/or ancestry, as indicated by PCA, ADMIXTURE and MANTEL test indicating complex local histories. There was poor correlation between pairwise genetic distance and geographical distance (0.33).
Our results of admixture estimation and hierarchical clustering reveal that genetically the populations of mainland India form four ancestry clusters (cross validation error minimum (0.52) compared to other competing models).
• TibetoBurman speaking populations of the northeast region
• Upper Caste groups of both northern(IE) and southern(DR) regions
• Austro-Asiatic(AA) speakers of central and eastern region
• DR speaking lower caste and tribal groups of southern region.
On inclusion of the Human Genome Diversity Panel (HGDP) data, we show that the A&N are close to the Polynasian populations, indicating early dispersal routes to Polynasia, Melanasia and Australia.