Saturday, December 2, 2023

Hope for better possum control as genome mapped

Neal Wallace
Researchers unpack the genetic code of brushtail possum – a pest in NZ and a treasured animal in Australia.
Reading Time: 2 minutes

Researchers have mapped the genetic code of the brushtail possum, which they say could provide new control options.

One potential option is utilising the gene responsible for carrying scent in urine and using molecules produced from these genes to lure possums towards a trap or to keep them away from pest-free areas.

The international group of researchers, led by scientists from the University of Otago, spent five years mapping the gene code, which included determining where and when genes are expressed.

The research could help control the possum in NZ where it is considered a pest. In Australia, however, the animals are treasured and protected, study lead, Associate Professor Tim Hore of Otago’s Department of Anatomy, said.

Having the full genetic code is important for both countries, with the respective contrasting population management evolving using DNA sequencing in areas such as chemical communication.

“Possums are nocturnal, so non-visual means of communication are really important,”  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.”

In the same way that mapping the human genome has allowed for significant molecular advances in human health, Hore told Farmers Weekly, this breakthrough will enable the development of molecular techniques to control the possum pest.

An immediate application is using DNA to determine the origins of possums that have repopulated areas previously free of the pest.

Molecular control techniques are more of a medium-term option and in the long term, he said, scientists could use DNA information to interrupt reproduction. 

Professor Dan Tompkins, Science Director at Predator Free 2050, said targeted, efficient and humane ways of removing pests are needed.

“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.”

More than $150 million a year is spent controlling possums in NZ.

Study co-author Dr Donna Bond of the University of Otago’s Department of Anatomy said possums were collected from Otago Peninsula and other sites near Dunedin and found to be genetic hybrids traced back to populations in Tasmania and the Australian mainland. 

“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,” she said.

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