Genetic diversity and admixture patterns in Indian populations

Area of Science:

• Population Genetics
• Human Evolutionary Studies
• Genomics

Background:

• India's population exhibits significant genetic diversity shaped by historical migrations and cultural variations.
• Previous research indicates two primary ancestral components in most Indian sub-populations.
• Understanding the genetic makeup of diverse Indian groups is crucial for evolutionary and anthropological studies.

Purpose of the Study:

• To perform a genome-wide survey of North and South Indian populations alongside international and Indian sub-populations.
• To analyze the genetic structure and diversity within and among Indian sub-populations.
• To investigate potential admixture events contributing to the genetic landscape of India.

Main Methods:

• Genome-wide data collection from North (N-In) and South (S-In) Indian individuals.
• Integration of data with HapMap Phase III and HUGO Pan-Asian SNP Consortium datasets.
• Multivariate statistical analyses including Multidimensional Scaling (MDS) and Principal Component Analysis (PCA).
• Population genetic statistics (Fst) and STRUCTURE analysis to infer population structure and admixture.

Main Results:

• Indian sub-populations formed distinct clusters separate from major global geographical regions in MDS and PCA.
• A loose agglomeration of Indian populations was observed, with two sub-populations showing proximity to East Asian populations.
• Fst values confirmed significant genetic diversity among Indian sub-populations.
• STRUCTURE analysis suggested evidence of additional admixture events within Indian populations.

Conclusions:

• Indian populations possess a unique genetic signature, distinct from other global populations.
• Significant genetic diversity exists among Indian sub-populations, reflecting complex demographic histories.
• Evidence supports ongoing or past admixture events that have shaped the genetic landscape of India.