Some scientists have hypothesized that Australian aboriginals received a portion of their DNA from an ancient hominid species called Homo erectus, which for a short time was contemporaneous with modern man. A recent study published in PNAS (Proceedings of the National Academy of the Sciences) set out to answer this question by analyzing mtDNA and Y-chromosome samples from aboriginals.
A total of 172 mtDNA and 522 Y-chromosome previously published and new sequences from aboriginal Australians and New Guineans were analyzed for mtDNA and Y-chromosome variation and were compared to the current world haplogroup tree. All of the mtDNA sequences were members of the M and N founder branches, and all of the Y-chromosome sequences fell into the C and F founder branches.
The results suggest that the Australian aboriginals are descendants of the same emigrant group that left Africa 50,000 to 70,000 years ago and populated Europe and Asia. At least from the small number of samples analyzed for this study, there does not seem to be any DNA contribution from Homo erectus.
The uniformity of the sequences suggests that once humans migrated into the region there was little other gene flow. This might explain why the Australian and New Guinean populations share phenotypic features that are unique to the region.
You can read more about this new study at National Geographic or NewScientist, or read the article online for free at PNAS. Additionally, Ron Scott at Scott Genealogy has provided a transcript (pdf) of an interview with Toomas Kivisild (one of the authors of the study and a name that many genetic genealogists will recognize).
The results suggest that the Australian aboriginals are descendants of the same emigrant group that left Africa 50,000 to 70,000 years ago and populated Europe and Asia.
Two loci does not a demographic study make. The results say nothing about autosomal contributions of any archaic species to aboriginal genomes. Those will be difficult (and maybe impossible) to detect unless they have adaptively introgressed into the aboriginal population. Simple introgression won’t leave a genomic signature clear enough to be detected using any known techniques.
Great point, especially since the Y chromosome and mtDNA represent only about 0.4% of the entire male genome. The results suggest that instead of looking at the Y chromosome or mtDNA, researchers can now focus on autosomal DNA to look for clues to aboriginal ancestry. My biggest complaint with the study was the sample size, which was only about 700 DNA samples. I’m sure these samples are difficult to obtain, but there’s still plenty of opportunity for mysterious DNA to be out there. Thanks for stopping by!
if they don’t share any ancestry with other groups of humans for more than 40,000 years, why are modern humans are considered to have emerged only 10,000 years ago in europe from cro-magnons? Are aboriginies considered to be something other than modern humans? Are native americans considered to be something else as well? What about isolated groups of african people like the pygmies or the people of south india, who are genetically similar to aboriginies? are these people biologically different according to the evolutionary terms applied to our species or does the definition of cro magnon man differing from modern man imply that it is a bogus concept?
Haha, right. The 10,000 year “modern human” lie was created by white anthropologists in a time when them aborigines were still legally considered “flora & fauna.” ACTUAL modern humans arose about 50,000, at least thats what my anthropology professor explained, which encompasses every known living human group from abos to native americans to papuans to certain ancient African tribes MUCH older than 10,000 years.
They are an archaic remnant population of the first modern humans to migrate out of Africa. There may likely have been some interbreeding with older homo species in Asia.