Could the Australian Aborigines have Descended from Three People?

Question

My anthropology professor claimed that certain genetic simulations showed that the Australian Aborigines could have descended from a population of only one man and two women. Those three people and their offspring could have sustained a genetically health population that's lasted tens of thousands of years.

I'm not really able to find the study she was referencing. Is it possible that a genetically healthy population, in this case the Indigenous Australians, could descend from just one man and two women? I know that the Samaritans are in a genetic crisis and their population never dropped lower than about 100.

Answer 1

No.

• Max Ingman and Ulf Gyllensten, Mitochondrial Genome Variation and Evolutionary History of Australian and New Guinean Aborigines, Genome Res. 2003. 13: 1600-1606, doi: 10.1101/gr.686603

This paper looked at the genetic diversity of Australian Aborigines and other indigenous populations in the area. It concludes:

The proposed genetic separation among Aboriginal populations could have occurred after a single large population movement to Australia or as the result of multiple migrations over the course of generations from a heterogeneous source population.

While they are vague about how many people are included in a "large" population movement, they quote another researcher with a similar, more precise figure.

Kayser et al. (2001) proposed that the high frequency of a unique haplotype in Australia is the result of a population expansion that started from a few hundred individuals.

However, they argue that:

there does not appear to be a corresponding loss of genetic diversity resulting from a bottleneck seen among mitochondrial lineages.

So, the number may be higher than just a few hundred.