A new study featured in the journal Proceedings of the National Academy of Sciences attempts to settle the 15-year-old debate on which people lived in the continent of Australia.
Researchers at Griffith University in Queensland have discovered DNA evidence that proves that Aboriginal Australians were in fact the original inhabitants of Australia contrary to the assumptions made in a 2001 paper.
In the previous research, Dr. Greg Adcock and his colleagues at the Australian National University (ANU) suggested that a different group of ancient human, known as the Mungo Man, may have been the first to occupy the continent long before the Aboriginal people. This was based on analyses of mitochondrial DNA retrieved from 40,000-year-old remains.
However, a recent re-analysis of the Mungo Man DNA revealed that it contained five different sequences from European people, which means the sample could have been exposed to contamination.
Griffith University Prof. David Lambert, who led the new study, affirmed that international researchers have had the same suspicion about the results of the 2001 paper.
He said the earlier sequences for the Mungo Man DNA were quite unusual. It promoted the idea that the Aboriginal people were not the original inhabitants of Australia and that they merely displaced the ancient group that was there before them.
Lambert pointed out that his group was not able to arrive at the same findings as those stated in the 2001 study, with the former using modern-day technology. This means the assumption that Aboriginal Australians were not the earliest people in the continent has no foundation.
Differences In DNA Sequencing Techniques
When Adcock and his team analyzed the Mungo Man sample, they made use of a DNA sequencing technique known as polymerase chain reaction (PCR). This particular method makes it possible for researchers to amplify even very short DNA sequences.
However, Lambert said one major problem with working on ancient DNA is that it is easy to produce copies and amplify DNA sequences that are not really from the original sample itself, such as those from scientists handling the specimen.
To avoid such scenarios in their work, Lambert and his colleagues used a different sequencing technique that amplified every DNA included in the Mungo Man sample. This allowed them to analyze aspects of the sample in detail including human, bacterial and even viral sequences.
The research team was not able to find any DNA that could help them identify the Mungo Man. This left scientists to rely on the analysis of the specimen's bones in order to properly identify the remains.
Prof. Colin Groves, a paleoanthropologist from ANU, said that the Mungo Man has an unusual set of bones but that these bones are not that much different from those seen on an Aboriginal person.
Despite welcoming the findings of the Griffin University paper, Prof. Alan Cooper, an expert on ancient DNA from the University of Adelaide, said they were not that "surprising."
He said that the sequences made by Adcock and his team have already been accepted by researchers as contamination since they first came out in 2001. They have been rejected by the field entirely and have not been used in any genetic study involving human evolution.
Mary Pappin, an Aboriginal elder from the Muthi Muthi group and one of those that serve as traditional custodians of the Mungo Man remains, said they have shown support for the Griffin University study by providing the researchers with access to the ancient specimen.
"I didn't think Australian Aborigines weren't the first people ... but anything that supports us in any way is good," Pappin said.