Aussies’ role in marsupial sequence

The groundbreaking first DNA sequence of a marsupial, announced earlier this week in the science journal Nature, included research by 11 Australians among its 63 international authors.

Scientists at the ARC Centre of Excellence in Kangaroo Genomics (KanGO) played key roles in the sequence of the grey, short-tailed opossum, according to KanGO Director Professor Jenny Graves, from the Research School of Biological Sciences at the Australian National University (ANU).

"KanGO contributed its knowledge about unique marsupial biology to this landmark opossum sequence project, making it particularly special," said Graves. "It tells us a lot about the way mammals evolved, and a lot about our own genes."

Proteins are very similar between marsupials and humans, with only 20% of the protein switches that control genes in humans new since marsupials split from other mammals.

Many of these switches evolved from DNA residue left behind by viruses. "Ancient viruses left their DNA all over the genome, and these became new switches to turn on or off banks of genes," said Dr Matthew Wakefield, a KanGO investigator now at the Walter and Eliza Hall Institute and an author on the Nature paper.

Australian scientists were first to propose sequencing a marsupial, however, a lack of Australian support saw the South American opossum chosen as the model.

Support from the Victorian Government is now seeing the kangaroo genome sequenced by the Australian Genome Research Facility in Melbourne, with help from collaborators in Texas.

"The kangaroo sequence is even more exciting now," Graves said. "Comparing the two distant species tells us what is peculiar to marsupials and what to humans and other placental mammals. This will help us to understand what makes mammals different."