Mitochondrial DNA variation in Australian aborigines: the spread of modern populations

Twelve Aboriginal people from Western Australia were examined for evidence of mitochondrial DNA polymorphism using 12 restriction endonucleases. Analyzed against a background population drawn from individuals of widespread geographic origin, Australians do not represent a depauperate mitochondrial gene pool. These 12 individuals showed the same range of functional diversity seen in the larger population sampled. Forty-two separate mitochondrial mutations were found among Aboriginal Australians, 35 probably due to single base substitutions and 7 due to length variation for specific regions of the genome. Such results reinforce the view that multiple populations have contributed to the spread of peoples in the Pacific. Mitochondrial DNA polymorphisms suggest that populations which contain these maternal lines can be traced back to one with a worldwide distribution roughly 350,000 years ago, corresponding to the emergence of Homo sapiens.