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Reconstructing the origin of Andaman Islanders
Kumarasamy Thangaraj1, Gyaneshwer Chaubey, Toomas Kivisild
1Centre for Cellular and Molecular Biology, Hyderabad-500 007, India.
Science (New York, N.Y.)
|May 14, 2005
Summary
The Andaman "Negrito" and Nicobar "Mongoloid" populations
Area of Science:
- Human evolutionary genetics
- Population genetics
- Ancient DNA analysis
Background:
- The origins of the Andaman and Nicobar islander populations have been historically ambiguous.
- Previous studies have offered limited insights into the genetic lineage of these isolated communities.
Purpose of the Study:
- To investigate the deep ancestral origins of the Andaman "Negrito" and Nicobar "Mongoloid" populations.
- To elucidate the migration patterns and genetic isolation of these island groups.
Main Methods:
- Analysis of complete mitochondrial DNA (mtDNA) sequences from Andamanese (Onge, Great Andaman) and Nicobarese individuals.
- Phylogenetic analysis to determine deep-rooting clades and common ancestry.
- Comparison of mtDNA lineages with global populations to infer migration history.
Main Results:
- Two distinct, deeply branching mtDNA clades were identified in Andamanese populations, originating from founder haplogroup M.
- These Andamanese clades show connections to lineages found in India, Africa, East Asia, New Guinea, and Australia.
- Nicobarese mtDNA sequences revealed a close genetic affinity with populations from Southeast Asia.
Conclusions:
- The Andamanese mtDNA lineages suggest survival in genetic isolation since an early "Out of Africa" migration by anatomically modern humans.
- The genetic data supports a distinct ancestral history for the Nicobarese, closely linked to Southeast Asian populations.
- Mitochondrial DNA analysis provides crucial insights into the peopling of the Andaman and Nicobar Islands.
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