Surprise DNA extracted from ancient poo

By Morgan Pettersson 29 November 2012
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The oldest DNA extracted from an Australian environment has been lifted from the Pilbara, WA.

A MASS OF 30,000-YEAR-OLD waste material has become the oldest environmental sample from which DNA has been obtained in Australia.

In another first, while it was previously thought unrealistic to extract DNA from hot, arid environments, the middens in question were located in the Pilbara region of WA, where temperatures soar.

Pilbara DNA extracted from hot, arid environment

Lead researcher Dáithí Murray, from Murdoch University’s Ancient DNA Research Lab, says this finding is interesting not only because it is the oldest recovered DNA, but because of its unusual location.

“It’s the oldest DNA that has been recovered in Australia and that’s pretty special for a hot, arid environment such as this one,” says Dáithí.

Dáithí says the location of the find has raised questions surrounding the formation and preservation of DNA. “Generally speaking, DNA survival is better in total frozen environments, while DNA in hot, arid environments is usually more controversial,” he says.

Dr Jeremy Austin from the Australian Centre for Ancient DNA at the University of Adelaide agrees that the findings indicate that DNA can be recovered from arid environments.

“They demonstrate that palaeo-DNA can be recovered from regions outside of the cold and temperate regions where most DNA research has been focused,” says Jeremy.

The midden material consisted of animal faeces and urine, plant and animal tissue as well as bone, hair and eggshells, which had cemented together over centuries.

Ancient DNA reveals the environment of the past

Researchers hope that comparing the extracted DNA to present-day plant and animal surveys will allow for a better understanding of the region, and how it has adapted over time to both natural and human impacts.

For example, the findings detected a range of now locally extinct plant and animal species not previously identified in the area, such as the common brushtail possum found in one midden in the Cavenagh Range, WA.

“These middens seem to be a really good source of ancient DNA that could help us get a better idea of the environment back in the past, and of these types of regions,” says Dáithí.

Jeremy hopes that the findings will open new possibilities of recovering DNA from areas previously not thought possible.

“The main implications are that DNA studies may be successful in sufficiently well-preserved remains, from non-frozen and non-temperate regions,” says Jeremy. “This might open the door for a range of studies in places like Australia, Africa and North America where DNA is typically not thought to survive due to high temperatures.”