I thought this excerpt from my book might be interesting to a larger population. The focus here is on the genetic and genealogical isolation of the Andaman Islands, not the actions of John Allen Chau. I understand there is strong feelings for and against his actions, but that is off topic for this thread.
The Andaman Islands in the Indian Ocean entered the news when John Allen Chau, a 26-year-old man from the United States was killed. He attempted to contact these isolated islanders in order to tell them about Jesus. News often repeated the claim that the islanders had been isolated for over 50,000 years ago. The islanders were famously hostile to outsiders, it seems, and do not welcomed outsiders into their midst. Some of this hostility is likely caused by the very recent history of British colonization of the islands.
The Andaman islanders are among the most isolated populations on earth. Their isolation, however, has not been total. The mythology of isolation is strong, but it is being rewritten by genetic research. The scientific literature tells an interesting story. For a long time, anthropologists have wondered on the origins of the islanders. They share characteristics with Africans, even though they are in Asia. This, in addition to the geographic isolation of the islands, suggested an interesting hypothesis. Perhaps the population arose from the initial expansions of African Homo sapiens over 50,000 years ago, that then remained isolated on the island. Two genetic studies, from 2005 and 2006, supported this hypothesis, showing divergence and isolation for tens of thousands of years ( 1 , 2 ). These two studies, however, only looked at small portions of the genome. Subsequent studies in 2013 used more genetic data from their neighbors, and variation across the whole genome. These analysis showed intermixing between the islanders and their neighbors, and a much more recent settlement of the island ( 3 – 6 ). The perception of the ancient and total isolation of the Andaman Islands was an artifact of incomplete genetic and historical data.
- K. Thangaraj et al. , Reconstructing the origin of Andaman Islanders. Science . 308 , 996 (2005).
K. Thangaraj, G. Chaubey, A. G. Reddy, V. K. Singh, L. Singh, Unique origin of Andaman Islanders: insight from autosomal loci. J. Hum. Genet. 51 , 800–804 (2006). https://www.nature.com/articles/jhg2006122
P. Endicott, Introduction: Revisiting the “Negrito” Hypothesis: A Transdisciplinary Approach to Human Prehistory in Southeast Asia. Hum. Biol. 85 , 7–20 (2013). https://www.jstor.org/stable/10.13110/humanbiology.85.issue-1-3
T. A. Jinam, M. E. Phipps, N. Saitou, T. H. P.-A. S. Consortium, Admixture Patterns and Genetic Differentiation in Negrito Groups from West Malaysia Estimated from Genome-wide SNP Data. Hum. Biol. 85 , 173–188 (2013). http://www.bioone.org/doi/abs/10.3378/027.085.0308
G. Chaubey, P. Endicott, The Andaman Islanders in a Regional Genetic Context: Reexamining the Evidence for an Early Peopling of the Archipelago from South Asia. Hum. Biol. 85 , 153–172 (2013). http://www.bioone.org/doi/abs/10.3378/027.085.0307
I. Pugach, F. Delfin, E. Gunnarsdottir, M. Kayser, M. Stoneking, Genome-wide data substantiate Holocene gene flow from India to Australia. Proc. Natl. Acad. Sci. 110 , 1803–1808 (2013).