DNA, Aboriginal Australians, dating and voyaging
Speculated migratory routes in the days of Sahul – no dates given, probably wisely
I watched a documentary this morning that was more confusing than enlightening, about the travels and wanderings of ancient humans including those who arrived in the land we now call Australia, perhaps as far back as 60,000 years ago. So I write this to try to clarify things for myself. Wikipedia presents the study on all this as ongoing, which is in accord with the documentary. Years ago, the story went that claims of a 60,000 year history here were exaggerated, and a figure close to 40,000 years was presented. But here’s a Wikipedia update:
While there have been genomic studies placing arrival as late as 43,000 years ago, a 2025 study suggests that the peopling of Australia happened around 60,000 years ago, via two distinct routes.
In those early days there was a continent we’ve called Sahul, with Australia being joined to New Guinea and other islands, including perhaps Tasmania in the south, so it was via a mixture of island-hopping and crossing land bridges that these people arrived from South-East Asia. With sea levels rising at the start of the Holocene, around 12,000 years ago, these people became more isolated on the mainland.
But DNA studies are muchly complicating the picture, and even the most basic research into this (by me) shows that there’s plenty of nastiness in the air about the first Aboriginal arrivals in this land – especially from white Aussies, whoda thunkit. For me, of course, it isn’t a life-and-death matter as to whether the first human arrivals occurred 50,000 or 65,000 years ago, or earlier, or later. What’s most interesting is that DNA is showing that our ancestors were on the move earlier and more regularly than was previously thought. A research article published in Science Advances in late November last year (2025), with some 26 authors named, has this to say in its abstract:
Here, we exhaustively analyze an unprecedentedly large mitogenome dataset (n = 2456) encompassing the full range of diversity from the indigenous populations of Australia, New Guinea, and Oceania, including a lineage related to those of New Guinea in an archaeological sample from Wallacea. We assess these lineages in the context of variation from Southeast Asia and a reevaluation of the mitogenome mutation rate, alongside genome-wide and Y-chromosome variation, and archaeological and climatological evidence. In contrast to recent recombinational dating approaches, we find support for the long chronology, suggesting settlement by ~60 ka via at least two distinct routes into Sahul.
So, a mitogenome dataset looks at large mitochondrial DNA sequences, and Wallacea relates to the Wallace line through central Indonesia, and it’s ‘defined by deep-water straits and high biodiversity endemism, acting as a “living laboratory” of evolution’ (Wikipedia). I’m obviously no expert, but even a little reading tells me that mutation rates are both key and highly contested. The article is long and highly technical and will undoubtedly be controversial, but it seems there has for a while been a mismatch between archaeological and fossil records and what has been understood from the genomics, and this study has found a way to combine them more or less satisfactorily. How this will eventually play out is of course another story. What it also suggests, I think, is that there has been more than one long-ago movement into Sahel from different points north, and that humans have been effective voyagers for longer than we previously thought possible. And right now I’m pondering over how I can get my head around it all….
Anyway, this is just an intro, I’ll explore this further in future posts
References
https://en.wikipedia.org/wiki/Aboriginal_Australians
https://www.dark-emu-exposed.org/home/the-myth-of-65-thousand-years-the-genetic-dna-of-aboriginals (a strange mixture of science and racism)
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