Koala Genomics to Help Conserve Koalas across the Species Range

Recently, our news has been overtaken by the impact of the 2019/20 bushfires and now we want to share what else we have been working on this year. Since 2014, Science for Wildlife has been involved in collaborative work on koala genomics, using a technique that looks at whole-genome DNA to get more information than ever before from the genetic code. With this information, we aim to inform species management.

Particularly since the bushfires, which had a devastating impact on koalas and their habitats, there is a need to actively manage koala populations with the aim of recovering their numbers. For that to be effective, it’s vital to have the best information on how koalas differ across the species range.

Koalas in Victoria and South Australia get up to 14kg in size and have thick fur, while up in Queensland they only reach 8kg and have thinner fur; they are adapted to different climates and habitats and their genes code for this physical variation. From this, we know that you wouldn’t move a koala from QLD to VIC, or vice versa but what we didn’t know was on a smaller scale, where are the management boundaries? Could you or should you, for example, translocate koalas that live 50km apart in similar habitats? With any threatened species it is crucial to conserve what is left of their genetic diversity, as that is what allows them to adapt to selection pressures and persist over time.

While many genetic studies of koalas have been undertaken, most are at a local to regional level, use different methods and target few and varied sections of the genome, so the results are difficult to compare between studies or koala populations. There has been no standardised test used on koalas across the species range.

The first stage of our work was undertaken in collaboration with researchers from James Cook University (JCU), the University of Sydney and San Diego Zoo Global, with PhD student Shannon Kjeldsen. That study identified genetic markers that are informative across the species range using the new technology whole-genome DNA, so we could identify how different koalas are from each other, if they are related, which populations are most genetically diverse and other information that will help to prioritise management actions. The study looked at koalas in 21 populations from SA to QLD, and a key finding from that for our other work was that koalas in the Blue Mountains hold the highest level of genetic diversity.

Last year Science for Wildlife received a three-year grant under the NSW Koala Strategy’s Koala Research Plan, which provided funding towards our field studies of koalas across the Greater Blue Mountains plus funding for a 2nd stage collaborative genomics project with JCU. The 2nd stage is aimed at developing a SNP (Single Nucleotide Polymorphism) marker assay that researchers across the country can use as a tool to run a low-cost and highly informative genomic assessment on any koala and compare the results to a database of over 1,500 koalas from over thirty populations. This tool will be incredibly useful for management of koalas both in the wild and captivity to guide translocations, captive breeding and even habitat restoration and corridors to reconnect koala populations.

The SNP tool will help us to determine koala population structure and will also use fitness-related markers including immunity, sex, diet and pathogen (Koala Retrovirus) markers to gain a holistic understanding of the health of koala populations across Australia.

Lily Donelly has taken on this project as part of her PhD at James Cook University, with supervision from Professor Kyall Zenger and Dr Conrad Hoskin at JCU, Dr Kellie Leigh at S4W, and Dr Matthew Lott from the Australian Centre for Wildlife Genomics at the Australian Museum who we are all delighted to have as a new project partner.

Lily says:

“I am excited to be working with this incredible team on such an important project. We want this research to include different types of genetic markers for an integrated approach across the koala genome, to better understand the diversity and adaptability of koalas across their range. The project will provide a universal genome tool and a baseline for future koala molecular studies.”

It’s a highly technical but exciting project and will provide a much-needed standardised tool to inform koala management from the local level to the species level. We look forward to sharing results as they come in.