Genetic evidence for the colonization of Australia

Abstract

Mitochondrial DNA (mtDNA), Y-chromosome and, more recently, genome studies from living people have produced powerful evidence for the dispersal of modern human populations. The prevailing model of global dispersion assumes an African origin in which Australia and the American continents represent some of the extreme regions of human migration, though the relative timing of dispersal events remains debatable. Here, a focus on Australia and New Guinea discusses currently available genetic evidence from the two regions, compared with that from Asia. Mt haplotypes indicate ancient ancestry for both Australia and New Guinea peoples, with evidence of some shared genetic connection and other unshared haplogroups apparently specific to both places. Migration into Sahul from south-east Asia may have been by more complex routes than only along a ‘southern coastal route’, raising the question of possible common ancestry in central or northern Asia for some Australian and American peoples for which current genetic evidence is tenuous. Although current dating methods for genetic diversity rely heavily on several assumptions, best estimates provide support for archaeological dates, indicating that, relative to the colonization of America, Australia was inhabited very early. Genetic diversity of living descendants of Australia’s founding populations is informative for dispersal within Australia and for understanding complex population histories of Asia.