Australasian Science: Australia's authority on science since 1938

DNA Survives the Heat

By Stephen Luntz

Ancient DNA in the Pilbara may give us unprecedented insights into past climate.

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DNA generally does not survive well in very hot climates, so for Daithi Murray the discovery of 30,000-year-old sequences from the Pilbara was something of a surprise. As a PhD student at Murdoch University, the Pilbara work is not even Murray’s main focus, but it could fill a frustrating gap in our knowledge about the world’s ancient climates.

Arid zones are hard places in which to establish climatic history. There are no ice cores and seldom any stalactites to incorporate clues about the temperature of the planet as they grow. Fossils can be thin on the ground, and where pollen is found its species can be very hard to identify.

However, Murray has helped reveal a potentially rich source of information about the ancient climate and ecology of some of the most forbidding places on Earth, through the extraction of DNA from 30,000-year-old middens in the Pilbara.

Stick-nest rats once built nests or middens out of material they scavenged from the surrounding territory. They used their own excretions to cement these into impermeable masses. While they once roamed widely across Australia’s drier lands, the lesser stick-nest rat is now probably extinct and its greater cousin is restricted to a few islands and protected areas.

Fossils and bits of pollen have been extracted from these middens in the past, along with those of similar species in North...

The full text of this article can be purchased from Informit.