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How to catch a koala

by Dr. Luke Silver

Until recently, the majority of research in the Australasian Wildlife Genomics Group occurred on the Tasmanian devil and trapping these marsupial carnivores is quite a straightforward process. Setting a trap overnight baited with a tasty piece of fresh meat to lure the devils inside. Recently, I was lucky enough to be invited to Kangaroo Island to help out on a koala field trip. It turns out trapping herbivorous marsupials is a far more demanding task as unfortunately you cannot lure a koala with a fresh branch of Eucalyptus leaves.

Can you spot the Koala in the trees?

Firstly, you have to actually find the koala in their environment, which can range of extremely tall Eucalyptus trees to highly dense shrubbery regions of bush. Fortunately, n Kangaroo Island koalas are so numerous locating one is not as difficult a task in areas such as NSW and QLD where koala numbers a much lower. After finally locating a koala the real work begins, coaxing the individual out of its comfortable and safe perch within the tree. This is best achieved by using an extendable pole with a piece of fabric attached to the end and simply waving this in front of the koala, who in ideal circumstances slowly backs down the tree trunk to height where they can be captured. Often, this is not the case, with koalas using any avenue possible to escape, including jumping to another nearby branch or tree. Being able to go into the field and see the animals we work up close is just one of the perks of working in wildlife research.

Koalas in trees

Author

Luke Silver

Luke Silver (PhD Student) is using genomic data to
investigate immune genes in Australian marsupials with a focus on koalas where he is using resequenced genomes to examine patterns of diversity in functional and neutral regions of the genome across the entire east coast of Australia. This work will be used to inform conservation and management decisions in the fight to save our threatened species.

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Koalas and Chlamydia: How can genomics help?

by Luke Silver (PhD Student) 

The mention of a koala infected with Chlamydia will often be met with rounds of laughter or even concern, “can I get Chlamydia from touching a koala?” For koalas, Chlamydia is no laughing matter with up to 100% of individuals in some populations infected with the bacteria. In many cases infection will lead to blindness, “wet bottom” as a result of bladder infection, infertility and eventually death. Unfortunately, unlike humans, koalas are unable to go to the doctor and receive treatment for the infection. Often koalas are taken to veterinary hospitals after a human interaction (such as vehicle strike or a dog attack) and it is there the infection is noticed and treatment can be administered.

Genomics is the study of the genes and nucleotides contained within an individual’s genome. By studying the genomics of koalas, we have been able to identify important genes which play a vital role in helping a koala clear a Chlamydia infection. One of these genes is a part of the major histocompatibility complex, or MHC, known for its vital role in recognition of pathogens. We are now using the whole genomes of over 400 koalas to investigate how diverse the MHC genes of koalas are across their entire range from northern Queensland to South Australia. A high level of genetic diversity in the MHC results in an individual or population being able to recognise a wider array of pathogens and may be linked to the health of this endangered marsupial. Scientists in other labs are attempting to develop a vaccine which can prevent koalas from contracting the infection in the first place which has shown promising results in early phase testing.

Finally, fortunately you are unable to catch Chlamydia from holding or touching a koala as the species which infects koalas is different from the species which infects humans.

Author

Luke Silver

Luke Silver (PhD Student) is using genomic data to
investigate immune genes in Australian marsupials with a focus on koalas where he is using resequenced genomes to examine patterns of diversity in functional and neutral regions of the genome across the entire east coast of Australia. This work will be used to inform conservation and management decisions in the fight to save our threatened species.

Koala Genome Survey: an open data resource to improve conservation planning

Type: Journal Article

Reference: Hogg, C. J., Silver, L., McLennan, E. A., & Belov, K. (2023). Koala Genome Survey: An Open Data Resource to Improve Conservation Planning. Genes, 14(3), 546. doi: 10.3390/genes14030546

Summary

Genome sequencing is a powerful tool that can inform the management of threatened species. Koalas (Phascolarctos cinereus) are a globally recognized species that captured the hearts and minds of the world during the 2019/2020 Australian megafires. In 2022, koalas were listed as ‘Endangered’ in Queensland, New South Wales, and the Australian Capital Territory. Populations have declined because of various threats such as land clearing, habitat fragmentation, and disease, all of which are exacerbated by climate change. Here, we present the Koala Genome Survey, an open data resource that was developed after the Australian megafires. A systematic review conducted in 2020 demonstrated that our understanding of genomic diversity within koala populations was scant, with only a handful of SNP studies conducted. Interrogating data showed that only 6 of 49 New South Wales areas of regional koala significance had meaningful genome-wide data, with only 7 locations in Queensland with SNP data and 4 locations in Victoria. In 2021, we launched the Koala Genome Survey to generate resequenced genomes across the Australian east coast. We have publicly released 430 koala genomes (average coverage: 32.25X, range: 11.3–66.8X) on the Amazon Web Services Open Data platform to accelerate research that can inform current and future conservation planning.

See all our publications HERE!

ABC Radio National: Will any Koalas be left in the Australias East by 2050

Being one of Australia’s cutest animals hasn’t prevented its slide towards extinction. 

Reporter Rachael Brown investigates what is being done to try to curb the koala’s declining population:

Listen to the full broadcast here: https://www.abc.net.au/radionational/programs/backgroundbriefing/will-any-koalas-be-left-in-australias-east-by-2050/13953818