The first large-scale study of the genetics of Aboriginal Australians has hinted at the origins of other non-African peoples, as well as the way the population of Australia evolved over 50,000 years.
Professor Eske Willerslev of Cambridge University sequenced the genomes of 83 Aboriginal Australians, along with 25 people from Papua New Guinea. The findings support the theory that a single migration 72,000 years ago contained the ancestors of most humans outside Africa.
Nevertheless, those pioneers found a world with other hominins already occupying plenty of space. Interbreeding with Neanderthals and Denisovans has already been established. In Nature, Willerslev presents evidence supporting the new theory of interbreeding with a further, unknown species.
The paper also confirms that, some fourteen thousand years after leaving Africa, the ancestors of Aboriginal Australians and Papuans separated from those who went on to conquer the rest of the world.
St John’s College, University of Cambridge
Venturing into more mysterious territory, Willerslev sheds light on the curious cultural change that spread across Australia around 4,000 years ago, starting in the northeast. What triggered such an event after a long period of stability is not known, but the paper reports on genetic evidence that supports linguistic and archaeological pointers.