Scientists may have pinpointed direct descendants of the first humans to migrate out of Africa into Asia. They could be the aboriginal inhabitants of the Andaman Islands in the Bay of Bengal, who have long been noted for their resemblance to African pygmies. Some convergence of features--dark skin and small, gracile form--is to be expected in peoples who have evolved in the tropics. But a recent DNA study of hair from Andamanese individuals, collected in 1907 by British anthropologist Alfred R. Radcliffe-Brown, suggests a closer connection.
Carlos Lalueza Fox, a postdoctoral fellow at the genetics laboratory of Erika Hagelberg at the University of Cambridge, had extracted DNA from 42 out of 70 hair samples and amplified a short segment of DNA from the mitochondria. Known as mtDNA, such DNA is less directly related to physical characteristics than chromosomal DNA and is therefore believed to be less sensitive to the pressures of natural selection. Fox and Hagelberg found that the sequences of base pairs in the mtDNA fragments clustered closer to African populations--especially southern African pygmies--than to Asian ones.