The CARD9 Gene in Koalas (): Does It Play a Role in the -Koala Interaction?

is a genus of fungal pathogens that can infect and cause disease in a range of host species and is particularly prominent in koalas (). Like other host species, koalas display a range of outcomes upon exposure to environmental from external nasal colonization to asymptomatic invasive infection and, in rare cases, severe clinical disease resulting in death. Host factors contributing to these varied outcomes are poorly understood.

A novel multi-variate immunological approach, reveals immune variation associated with environmental conditions, and co-infection in the koala (Phascolarctos cinereus).

External signs of disease are frequently used as indicators of disease susceptibility. However, immune profiling can be a more effective indicator to understand how host responses to infection may be shaped by host, pathogen and environmental factors. To better inform wildlife health assessment and research directions, we investigated the utility of a novel multivariate immunophenotyping approach examining innate and adaptive immune responses in differing climatic, pathogen co-infection and demographic contexts across two koala (Phascolarctos cinereus) populations in New South Wales: the Liverpool Plains (LP), and Southern Highlands to South-west Sydney (SHSWS).

Expanding the known distribution of phascolartid gammaherpesvirus 1 in koalas to populations across Queensland and New South Wales.

Koala populations across the east coast of Australia are under threat of extinction with little known about the presence or distribution of a potential pathogen, phascolartid gammaherpesvirus 1 (PhaHV-1) across these threatened populations. Co-infections with PhaHV-1 and Chlamydia pecorum may be common and there is currently a limited understanding of the impact of these co-infections on koala health. To address these knowledge gaps, archived clinical and field-collected koala samples were examined by quantitative polymerase chain reaction to determine the distribution of PhaHV-1 in previously untested populations across New South Wales and Queensland.

Development of diagnostic and point of care assays for a gammaherpesvirus infecting koalas.

The recent listing of koala populations as endangered across much of their range has highlighted the need for better management interventions. Disease is a key threat to koala populations but currently there is no information across the threatened populations on the distribution or impact of a gammaherpesvirus, phascolarctid gammaherpesvirus 1 (PhaHV-1). PhaHV-1 is known to infect koalas in southern populations which are, at present, not threatened.

Future-proofing the koala: Synergising genomic and environmental data for effective species management.

Climatic and evolutionary processes are inextricably linked to conservation. Avoiding extinction in rapidly changing environments often depends upon a species' capacity to adapt in the face of extreme selective pressures. Here, we employed exon capture and high-throughput next-generation sequencing to investigate the mechanisms underlying population structure and adaptive genetic variation in the koala (Phascolarctos cinereus), an iconic Australian marsupial that represents a unique conservation challenge because it is not uniformly threatened across its range.

Differences in constitutive innate immunity between divergent Australian marsupials.

Understanding immunity in wildlife populations is important from both One Health and conservation perspectives. The constitutive innate immune system is the first line of defence against pathogens, and comparisons among taxa can test the impact of evolution and life history on immune function. We investigated serum bacterial killing ability (BKA) of five marsupial species that employ varying life history strategies, demonstrated to influence immunity in other vertebrates.

First evidence of deviation from Mendelian proportions in a conservation programme.

Classic Mendelian inheritance is the bedrock of population genetics and underpins pedigree-based management of animal populations. However, assumptions of Mendelian inheritance might not be upheld in conservation breeding programmes if early viability selection occurs, even when efforts are made to equalise genetic contributions of breeders. To test this possibility, we investigated deviations from Mendelian proportions in a captive metapopulation of the endangered Tasmanian devil.

A demonstration of conservation genomics for threatened species management.

As species extinction rates increase, genomics provides a powerful tool to support intensive management of threatened species. We use the Tasmanian devil (Sarcophilus harrisii) to demonstrate how conservation genomics can be implemented in threatened species management. We conducted whole genome sequencing (WGS) of 25 individuals from the captive breeding programme and reduced-representation sequencing (RRS) of 98 founders of the same programme.

Too much of a good thing? Finding the most informative genetic data set to answer conservation questions.

Molecular markers are a useful tool allowing conservation and population managers to shed light on genetic processes affecting threatened populations. However, as technological advancements in molecular techniques continue to evolve, conservationists are frequently faced with new genetic markers, each with nuanced variation in their characteristics as well as advantages and disadvantages for informing various questions. We used a well-studied population of Tasmanian devils (Sarcophilus harrisii) from Maria Island, Tasmania, to illustrate the issues associated with combining multiple genetic data sets and to help answer a question posed by many population managers: which data set will provide the most precise and accurate estimates of the population processes we are trying to measure? We analysed individual heterozygosity (as internal relatedness, IR) of 96 individuals, calculated using four genetic marker types (putatively neutral microsatellites, major histocompatibility complex-linked microsatellites, reduced representation sequencing, and candidate region resequencing).