DNA research says Australian Aborigines arrived 50,000 years ago
But how reliable are the ‘molecular clocks’?
Published: 22 April 2017 (GMT+10)
Today’s feedback from Chris B. of Australia, concerns media reports about when Aboriginal people settled Australia. It’s answered by CMI’s Dr Tas Walker.
In recent years the media has reported ever increasing ages that the Aboriginal Australians have inhabited the continent, and progressively, figures of 10, 20 and up to 40 and 50 thousand years have been given. The evidence of these dates mostly come from artefacts like cave painting or rock engraving. Recently, however, these sorts of dates have been claimed to arise from comparing DNA of Australian Aboriginals with that of the people indigenous to the Highlands of New Guinea. The theory is that at one time they had the same genome, but, genetic drift over time can be seen by comparing the DNA, thus "counting back" to when they were one people.
Is this technique of genome comparison a valid way to date how long Aboriginal people have been living in Australia, or does the technique contain certain evolutionary assumptions? Does CMI have any information refuting such DNA based dating that you can kindly refer me to?
CMI’s Dr Tas Walker responds:
The dating technique you mention is called a ‘molecular clock’. It involves very sophisticated laboratory techniques for comparing DNA sequences. However, like all ‘scientific’ clocks, a date cannot be calculated without making a number of unprovable assumptions about the past (see Fatal flaw). The reason the technique gives long ages is because the rate of genetic change is calibrated to provide results consistent with the standard evolutionary long-age timescale. However, when the rate of genetic change is ‘calibrated’ against the rate actually measured in organisms at the present time the timescales are much shorter—consistent with the biblical timescale.
The article Evolutionary molecular genetic clocks—a perpetual exercise in futility and failure explains the principles of the molecular clock and discusses the problem with the method. In summary, genetic clock methods assume evolution and deep-time by calibrating against the paleontological timescale. In addition, the methods have multiple problems: 1) different genes/sequences give widely different evolutionary rates, 2) different taxa exhibit different rates for homologous (similar) sequences, and 3) divergence dates commonly disagree with paleontology despite being calibrated by it. And finally, the molecular clock idea is directly tied to the neutral model theory of evolution, which assumes mutations occur in the so-called junk DNA. However, recent discoveries undermine the idea of pervasive junk DNA, thus negating its foundational premise.
The article Empirical genetic clocks give biblical timelines shows that when measured rates of genetic change are applied, ‘molecular clocks’ yield ages consistent with the biblical timescale. The article concludes, “A straightforward empirical approach constricted to analyses within a single taxa, typically yields dates of not more than about 5,000 to 10,000 years. Thus, when the hypothetical evolutionary constraints are removed, and the data is analyzed empirically, biblical timelines are achieved.”
One recent media article about the dating of Aboriginal occupation of Australia was reported in Science Daily,1 based on research published in Nature.2 This analysed hair samples collected from Aboriginal people across Australia. The genetic relationships between people within Australia and outside Australia from this analysis are likely to be reasonable. All people on earth today are descended from the eight people who were on Noah’s Ark that came to rest in the Middle East, and so the emigration paths described in the paper would be compatible with the biblical account. However, the multi-thousand-year dates are not, for the reasons outlined above.
The article The dating game discusses various efforts to date Aboriginal remains, in particular the individuals dubbed Mungo Man and Mungo Woman, found in sand dunes in south-western New South Wales. This article was published in 2003 but is still relevant. It describes how published dates, based on a range of different methods, progressively rose higher and higher. In 1999, when researchers at Australian National University in Canberra published a date of 62,000 years, other evolutionary researchers objected. It created an international problem for theories of human evolution. Such an early occupation of Australia by Aborigines would require the whole out-of-Africa theory of human origins to be rewritten.
However, the new molecular clock researchers are not so ambitious, citing dates of 50,000 years. Perhaps some sort of a compromise is being sought by settling on a number that won’t run afoul of the out-of-Africa scenario but still have very old dates for Australian Aborigines.
These scenarios for Aboriginal occupation of Australia are based on evolutionary assumptions, and these contradict biblical history. Especially they ignore Noah’s global Flood. However, the Bible provides a solid interpretive framework for scientific investigations into human origins. The first Aboriginal settlers to Australia were descended from people as intelligent and inventive as all other people alive at that time. Like everyone else, they were descended from Noah, who built and managed the Ark, and from a people who developed an advanced civilization around the Tower of Babel. So, as the DNA research reveals, the Australian Aborigines were related to other people groups, including those in India and Papua New Guinea. This aspect of the DNA research fits nicely with the biblical account.
However, the idea that the Aboriginal people of Australia are a primitive culture that had not evolved as much as people from other cultures is wrong. It’s evolutionary racism. Rather, they lost some of their technological know-how when they reached Australia. This can happen in a generation if parents do not pass their culture onto their children, or if small populations become isolated. Perhaps it was this isolation and the pressure to cope with a worsening climate as the continent dried out after the post-Flood Ice Age. But, they, like all other peoples, are made ‘in the image of God’ (Genesis 1:26), to have a relationship with God.
In summary, the dates produced by the ‘molecular clock’ are not valid because it begins with an incorrect calibration and has numerous fatal problems. However, if measured mutation rates are used as calibration then dates consistent with biblical timescales are obtained. But the method still has problems, which is why scientists do not rely on the dates it produces until they have checked other research to decide which dates to accept. On the other hand, the genetic relationships between people groups revealed by DNA comparisons are likely to be reasonably sound, and may help sort out migration routes of people since disembarking from Noah’s Ark in the Middle East about 4,500 years ago.
All the best,
Scientist, Writer, Speaker
References and notes
- University of Adelaide, Aboriginal hair shows 50,000 year connection to Australia, ScienceDaily, 8 March 2017; www.sciencedaily.com/releases/2017/03/170308131131.htm. Return to text.
- Ray Tobler, Adam Rohrlach, Julien Soubrier, Pere Bover, Bastien Llamas, Jonathan Tuke, Nigel Bean, Ali Abdullah-Highfold, Shane Agius, Amy O’Donoghue, Isabel O’Loughlin, Peter Sutton, Fran Zilio, Keryn Walshe, Alan N. Williams, Chris S. M. Turney, Matthew Williams, Stephen M. Richards, Robert J. Mitchell, Emma Kowal, John R. Stephen, Lesley Williams, Wolfgang Haak, Alan Cooper. Aboriginal mitogenomes reveal 50,000 years of regionalism in Australia, Nature, 2017; DOI: 10.1038/nature21416. Return to text.