Genetic Study of Sinhalese and Adivasi in Sri Lanka

A recent study analyzing whole-genome sequence data of urban Sinhalese and two indigenous Adivasi clans in Sri Lanka reveals insights into their migratory history and genetic relationships, particularly in connection with Indian populations.

Key Findings

• Sinhalese and Adivasi are genetically closest to each other and South Indians.
• Within the Adivasi, the Interior and Coastal clans show genetic distinctions.

Migratory History and Linguistic Affinities

• Sinhalese Origins:
  • Previous theories suggested migration from northern India around 500 BC.
  • The study finds genetic similarities with Dravidian-speaking South Indian populations rather than northern groups.
• Genetic-Linguistic Discordance:
  • The Sinhalese speak an Indo-European language, suggesting North Indian links, yet genetically resemble South Indians.
  • Possible explanations include language transmission by a small elite group or genetic mixing with ASI populations.

Genetic Diversity and Population History

• Ancient Ancestry:
  • Adivasi have higher levels of ancient hunter-gatherer ancestry compared to Sinhalese and Sri Lankan Tamils.
  • Their genomes show signs of endogamy and lower genetic diversity.
• Population Dynamics:
  • Interior Adivasi experienced greater population size reduction than Coastal Adivasi, attributed to social or environmental pressures.

Methodological Approach

• Sample Size and Analysis:
  • Smaller sample sizes for Adivasi due to fragmented communities and high relatedness affecting genetic analyses.
  • The study effectively recaptured the population history despite limited samples.

Implications

The study underscores the complex migratory patterns and genetic interconnections between India and Sri Lanka, highlighting the diverse evolutionary trajectories of biological and cultural elements in South Asia.