Question

Of the multiregional versus Out-of-Africa hypotheses, which model is supported best by the data? Briefly state how the data support that particular model.

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Answer 1

The “Out Of Africa” hypothesis is supported to be the best. The theory suggests that all modern humans stem from a single group of Homo sapiens who emigrated from Africa 2,000 generations ago and spread throughout Eurasia over thousands of years. These settlers replaced other early humans (such as Neanderthals), rather than interbreeding with them.

The mitochondrial DNA (mtDNA) and Y chromosome DNA of Aboriginal Australians and Melanesians from New Guinea was compared with the various DNA patterns associated with early humans.The results showed that both the Aborigines and Melanesians shared the genetic features that have been linked to the exodus of modern humans from Africa 50,000 years ago.

There was no evidence of a genetic inheritance from Homo erectus, indicating that the settlers did not mix and so these people share the same direct ancestry as the other Eurasian peoples.

According to genesist Dr. Peter Forster, who led the research, “Although it has been speculated that the populations of Australia and New Guinea came from the same ancestors, the fossil record differs so significantly it has been difficult to prove. This evidence gives us a genetic link showing that the Australian Aboriginal and New Guinean populations are descended directly from the same specific group of people who emerged from the African migration.”

50,000 years ago,when the migration took place, Australia and New Guinea were joined by a land bridge and the region was also only separated from the main Eurasian land mass by narrow straits such as Wallace's Line in Indonesia. The land bridge was submerged about 8,000 years ago.

New study also explains the fossil and archaeological record in Australia is very different. The DNA patterns of Australian and Melanesian populations show that the population evolved in relative isolation. The two groups also share certain genetic characteristics that are not found beyond Melanesia. This suggests that there was very little gene flow into Australia after the original migration.