NORTH SENTINEL ISLAND, November 26, 2018 (Scientific American by M.Mukerjee): On November 17, 2018, when 26-year-old missionary John Allen Chau landed on North Sentinel Island in the Bay of Bengal in the hope of rescuing the natives from "the clutches of Satan," they predictably slew him. The American hoped to save souls but the self-styled missionary failed to comprehend that isolation ensures the Sentinel Islander's survival. The last tribe living in voluntary isolation in Asia, the Sentinelese kill almost everyone who lands on their shores. The strategy ensures distance from outsiders, protecting them from the diseases and social decay that have felled other tribes of the Andaman archipelago. Now, the attempts to retrieve Chau's body--in violation of his express wishes--threatens to unleash a cascade of events that would endanger the survival of this island's exceedingly vulnerable people.
It is hard to overstress how miraculous the continued existence of the Sentinel islanders is. Genetic studies of the contacted Andaman tribes indicate that they directly descend from modern humans who left Africa roughly 60,000 years ago. Traveling eastward along the coastlines of India, these wanderers eventually reached the Andaman Islands--some to stay, others to move further south toward Australia and Papua New Guinea. Intriguingly, the Andamanese may have derived 2 to 3 percent of their genes from an as-yet-unidentified hominin, but otherwise seem to have remained genetically isolated. Their languages constitute a separate language family--Andamanese--although linguist Anvita Abbi holds that it should be subdivided into two other families, Great Andamanese and Ang.
Much more of the history of the Andaman Islanders at "source" above.