The common brushtail possum is a nocturnal arboreal marsupial of the family Phalangeridae.
The species is native to Australia and invasive in New Zealand, and is the second-largest of the possums.
It is mainly a folivore (leaf-eater), but has been known to eat small mammals such as rats. In most Australian habitats, eucalyptus leaves are a significant part of the diet.
Like other marsupials, the brushtail possum gives birth to altricial young — gestation lasts only 17.5 days.
Possums at birth are hairless, without overt sexual differentiation and do not even possess full respiration capacity in the lungs.
The first 100 days of life in the pouch are spent moving very little and with eyes shut, completing organogenesis and growth while continuously suckling from a teat.
As such, it could be argued that the most major developmental transition for possums is at weaning and exit from the pouch around 6 months of age.
Despite this, physiological changes associated with extended lactation and weaning have not been well studied, particularly in a genome-wide manner.
“The common brushtail possum is a fascinating animal that is loved in one country and a cause of concern in another,” said University of Otago’s Dr. Tim Hore, corresponding author of the study.
“They are hunted in Aotearoa New Zealand for their fur, and controlled for conservation, but treasured and protected in Australia.”
“Having their full genetic code is important for both countries as efforts to manage their respective populations are being held back by the lack of this knowledge.”
“In New Zealand, where the possum is a harmful introduced species, we can use the information to help guide control and eradication strategies, by tracking and monitoring target populations on the basis of their genes.”
“But in the same way our work will also be useful for its conservation in Australia, where it is a valued native species.”
The authors uncovered where and when brushtail possum’s genes are expressed, and revealed surprising details about their population diversity, reproduction, and origins.
“Possums are nocturnal, so non-visual means of communication are really important,” Dr. Hore said.
“We uncovered possum genes responsible for carrying scent in urine, and found that although they are silenced in newborns, they are switched on in adults, particularly males.”
“Molecules produced from these genes could be used to lure possums towards a trap or keep them away from pest-free areas.”
“Through the Predator Free 2050 mission we are driving to eradicate possums — along with rats and stoats — from the whole of Aotearoa to protect native biodiversity, and we are always on the lookout for more targeted, efficient and humane ways of getting the job done,” said Professor Dan Tompkins, the science strategy manager at Predator Free 2050 Ltd.
“Deciphering their genetic code provides us with an invaluable new knowledge base that underpins and enables exploration of a range of better approaches to do just that, from possum-species toxins to fertility control, and the exciting new ideas leveraging scent communication proposed here.”
The researchers also uncovered new details regarding the establishment of brushtail possum in New Zealand from Australian populations.
Introduced in the 19th century to establish a fur trade, possums went on to become serious pests, damaging many forest ecosystems and killing native birds and some insects.
In comparison, they are a cultural and ecological treasure in their native range, where Southern Aboriginal tribes use their skins for cloaks, depicting images and stories on them throughout life.
“Possums from the study were collected from Otago Peninsula and other sites near Dunedin, but were genetic hybrids tracing back to discrete populations in Tasmania and the Australian mainland,” said University of Otago’s Dr. Donna Bond, first author of the study.
“Although the possums introduced in the 19th century were low in numbers, perhaps a few hundred, because they are mixed up from at least four different Australian populations, the New Zealand animals we tested had more genetic diversity than those from Australia.”
The team’s results were published in the journal Nature Communications.
D.M. Bond et al. 2023. The admixed brushtail possum genome reveals invasion history in New Zealand and novel imprinted genes. Nat Commun 14, 6364; doi: 10.1038/s41467-023-41784-8
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This article was first published by Sci.News on 17 October 2023. Lead Image: Common brushtail possums (Trichosurus vulpecula). Image credit: J.J. Harrison, https://www.jjharrison.com.au / CC BY-SA 2.5 Deed.