The Negritos are probably descendants of the indigenous Negroid populations of the Sunda landmass and New Guinea, predating the Austronesian peoples who later entered Southeast Asia.[7]
A number of features would seem to suggest a common origin for the Negritos and Negrillos (African Pygmies). No other living human population has experienced such long-lasting isolation from contact with other groups.[8]
Features of the Negrito include short stature, dark skin, woolly hair, scant body hair, and occasional steatopygia. The claim that Andamanese pygmoids more closely resemble Africans than Asians in their cranial morphology in a study of 1973 added some weight to this theory, before genetic studies pointed to a closer relationship with Asians.[8]
Multiple studies also show that Negritos from Southeast Asia to New Guinea share a closer cranial affinity with Australo-Melanesians.[7][9]
It has been suggested that the craniometric similarities to Asians could merely indicate a level of interbreeding between Negritos and later waves of people arriving from the Asian mainland. This hypothesis is not supported by genetic evidence that has shown the level of isolation which populations such as the Andamanese have experienced. However, some studies have suggested that each group should be considered separately, as the genetic evidence refutes the notion of a specific shared ancestry between the "Negrito" groups of the Andaman Islands, the Malay Peninsula, and the Philippines.[10]
A study on blood groups and proteins in the 1950s suggested that the Andamanese were more closely related to Oceanic peoples than Africans. Genetic studies on Philippine Negritos, based on polymorphic blood enzymes and antigens, showed they were similar to surrounding Asian populations.[8] Genetic testing places all the Onge and all but two of the Great Andamanese in the mtDNA Haplogroup M found in East Africa, East Asia, and South Asia, suggesting that the Negritos are at least partly descended from a migration originating in eastern Africa 60,000 years ago. This migration is hypothesized to have followed a coastal route through India and into Southeast Asia, which is sometimes referred to as the Great Coastal Migration.
Analysis of mtDNA coding sites indicated that these Andamanese fall into a subgroup of M not previously identified in human populations in Africa and Asia. These findings suggest an early split from the population of migrants from Africa; the descendants of these migrants would eventually populate the entire habitable world.[8] Haplogroup C-M130, Haplogroup O-2seen in dark-skinned Negritos like the Semang of Malaysia and Phillipeans Negritos, and haplogroup D-M174 are believed to represent Y-DNA in the migration.[11]
A recent genetic study found that unlike other early groups in Malesia, Andamanese Negritos lack the Denisovan hominin admixture in their DNA. Denisovan ancestry is found among indigenous Melanesian and Australian populations between 4–6%.[12]
Posted By: Steve Williams
Sunday, February 1st 2015 at 11:34AM
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