News - 01 July 2024

Bilby genome sequencing a world first

Greater bilby (Macrotis lagotis). Photograph: Ken Griffiths

A consortium of scientists led by the University of Sydney has sequenced the genome of the Australian bilby.

This world-first first mapping of the bilby’s genetic blueprint includes biological information on how they grow and evolve, and will play a vital role in conserving the threatened species.

Around the size of a rabbit, and often referred to as the Aussie Easter bunny, the bilby is a comic-book concoction of large ears, elongate snout, silky pale blue-grey fur, black and white tail and backward-facing pouch. It emerges from its burrow at night to hunt, using strong forelimbs and long claws to find food and turn over soil and organic matter.

Before European settlement, two species ranged the continent—the lesser bilby, which died out in the 1930s, and the greater bilby, which now exists in only 20 percent of its former habitat range, the central deserts of Western Australia and the Northern Territory.

Populations nosedived after the introduction of predatory cats and foxes, and were outcompeted for food by rabbits. Today, small wild populations are managed by Indigenous rangers while 6000 bilbies live in the metapopulation housed in fenced sanctuaries, on islands and in zoos.

“Using DNA from two deceased zoo bilbies—male and female—we have produced one of the highest-quality marsupial genomes to date,” says University of Sydney lead researcher Professor Carolyn Hogg. “It offers insights into biology, evolution and population management.”

Professor Carolyn Hogg @ University of Sydney. Courtesy: University of Sydney

The team also created the first genome for the extinct lesser bilby from the skull of a specimen collected in 1898.

“The Greater bilby reference genome is one of the highest-quality marsupial genomes to date, presented as nine pieces, representing each of the bilby chromosomes,” said Professor Hogg. “It offers insights into biology, evolution, and population management.”

A reference genome is the equivalent of having a puzzle box lid - a way of knowing what all the DNA puzzle pieces mean.

“It helps us understand what gives bilbies their unique sense of smell, and how they survive in the desert without drinking water.” said Professor Hogg.

The team also used the genome to develop a more precise scat-testing method to complement existing traditional land-use practices by Indigenous rangers.

“We know a lot about bilbies—where they live, what they eat and how to track them,” said ranger Scott West from the Kiwirrkurra Indigenous Protected Area in Western Australia.

“The DNA work will help us check if bilbies are related, where they are from and how far they have travelled. Using old-ways and new-ways together helps us get good information about bilbies and how to look after them. This is what two-way science is.”