The Andaman Islanders in a regional genetic context: reexamining the evidence for an early peopling of the archipelago from South Asia.

The indigenous inhabitants of the Andaman Islands were considered by many early anthropologists to be pristine examples of a "negrito" substrate of humanity that existed throughout Southeast Asia. Despite over 150 years of research and study, questions over the extent of shared ancestry between Andaman Islanders and other small-bodied, gracile, dark-skinned populations throughout the region are still unresolved. This shared phenotype could be a product of shared history, evolutionary convergence, or a mixture of both. Recent population genetic studies have tended to emphasize long-term physical isolation of the Andaman Islanders and an affinity to ancestral populations of South Asia. We reexamine the genetic evidence from genome-wide autosomal single-nucleotide polymorphism (SNP) data for a shared history between the tribes of Little Andaman (Onge) and Great Andaman, and between these two groups and the rest of South and Southeast Asia (both negrito and non-negrito groups).