Two teams of genetic researchers have sequenced the genome of the numbat (Myrmecobius fasciatus), a critically endangered Australian insectivorous marsupial and the last surviving member of the family Myrmecobiidae. The genome map will enable scientists and conservationists to make better informed decisions about how to safeguard the species into the future.
The numbat (Myrmecobius fasciatus). Image credit: Seashalia Gibb.
The numbat is a colorful marsupial between 35 and 45 cm (14-18 inches) long, including the tail, and weighing up to 700 g.
Also known as the noombat or walpurti, the numbat is the only termitivorous marsupial, consuming up to 20,000 termites per day.
Its high visual acuity, powerful front claws and sense of smell enables the numbat to locate and dig out termite mounds and sub-surface structures.
Its extremely long tongue allow the numbat to then extract termites from within the mounds.
The numbat is also unique amongst marsupials as it is the only diurnal and marsupial.
In addition, it has a variety of important adaptations to an arid environment including regular torpor.
Historically, numbats inhabited the arid and semi-arid regions of Australia. However, populations have declined by more than 99% due to habitat degradation and predation.
It is estimated there are only 1,000 individuals remaining in Western Australia.
As such, the numbat is currently listed as Endangered on the IUCN Red List and Vulnerable under the Australian Federal Government’s Environment Protection and Biodiversity Conservation Act 1999.
“The numbat was on the verge of extinction during the 20th century, but extensive conservation efforts as well as government and community intervention have led to a gradually increasing population,” said Dr. Parwinder Kaur, a researcher in the School of Agriculture and Environment at the University of Western Australia.
“With 1,000 numbats left in the wild, the genomic resource will open new doors for numbat conservation efforts as well as for our scientists on the front line, fighting the very genetic diseases threatening to exterminate numbats.”
To sequence the numbat genome, the researchers used samples from female and male individuals housed at Perth Zoo.
“Perth Zoo is the only zoological institution in the world to breed numbats and since 1993, more than 220 have been bred at the zoo — and released into the wild,” said Dr. Kaur, who is a member of the numbat genome project, a collaboration between the University of Western Australia, DNA Zoo, Aiden Lab at Baylor College of Medicine, the Pawsey Supercomputing Centre, the Australian Government and the Government of Western Australia.
The scientists then identified a total of 21,465 protein-coding genes in the 3.42-billion-base genome of the numbat.
“To investigate adaptation to the numbat’s termitivorous diet and arid/semi-arid range, we interrogated the most highly expressed transcripts within the tongue and manually annotated taste, vomeronasal and aquaporin gene families,” said University of Sydney’s Dr. Emma Peel and her colleagues from the University of Sydney, Hokkaido University, and Japan Monkey Centre.
“Antimicrobial proteins and proteins involved in digestion were highly expressed in the tongue, as expected.”
“Similarly, umami taste receptors were also expressed in the tongue, however sweet taste receptors were not expressed in this tissue.”
“This pattern of taste receptor expression, combined with the putative contraction of the bitter taste receptor gene repertoire in the numbat genome, may indicate a potential evolutionary adaptation to their specialized termitivorous diet.”
“Vomeronasal and aquaporin gene repertoires were similar to other marsupials and have not undergone expansion or contraction.”
“The mapping of the numbat genome is a wonderful scientific achievement which will play a crucial role in our conservation efforts,” said Reece Whitby, the WA Minister for Environment and Climate Action.
“Western Australia is a biodiversity hotspot with some of the most unique wildlife in the world.”
“This wildlife needs to be understood and protected, and the partnership between Perth Zoo and DNA Zoo will help to achieve this.”
“A big thank you to everyone involved and I look forward to seeing more exciting results.”
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