Genetic diversity in natural and introduced island populations of koalas in Queensland

Lee, Kristen E.; Seddon, Jennifer M.; Johnston, Stephen D.; FitzGibbon, Sean; Carrick, F. N.; Melzer, Alistair; Bercovitch, Fred B.; Ellis, William A. H.

doi:10.1071/zo12075

Cited by 22 publications

(32 citation statements)

References 50 publications

(19 reference statements)

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“…Interestingly, the koalas on St. Bees Island, and other island koala populations, had lower levels of genetic diversity than those from Southeast Queensland where they originated (37). The St.…”

Section: Discussionmentioning

confidence: 94%

Koala Retrovirus Diversity, Transmissibility, and Disease Associations

Zheng¹,

Pan²,

Tang

et al. 2020

Preprint

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Background Koalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n=78), two Australian zoos (n=27) and wild-caught (n=21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data. Results All koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. Conclusions Our results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.

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Section: Discussionmentioning

confidence: 94%

Koala Retrovirus Diversity, Transmissibility, and Disease Associations

Zheng¹,

Pan²,

Tang

et al. 2020

Preprint

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“…The leaves koalas eat provide most of their water needs, so this covariate may act as a surrogate for tree condition and leaf moisture content [52,53]. Areas surrounding prominent sources of fresh water in other parts of southeast Queensland, for example North Stradbroke Island, also support relatively high numbers of koalas [54]. Such findings thus provide support for research that suggests extreme events, such as droughts and heatwaves, that affect water availability will have both direct and indirect consequences for koalas and other endothermic species that use evaporative cooling for thermoregulation [55,56].…”

Section: Discussionmentioning

confidence: 99%

Using virtual reality and thermal imagery to improve statistical modelling of vulnerable and protected species

Leigh

Heron

Wilson

et al. 2019

Preprint

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22Biodiversity loss and sparse observational data mean that critical conservation 23 decisions may be based on little to no information. Emerging technologies, such as airborne 24 thermal imaging and virtual reality, may facilitate species monitoring and improve 25 predictions of species distribution. Here we combined these two technologies to predict the 26 distribution of koalas, specialized arboreal foliovores facing population declines in many 27 parts of eastern Australia. For a study area in southeast Australia, we complemented ground-28 survey records with presence and absence observations from thermal-imagery obtained using 29 Remotely-Piloted Aircraft Systems. These field observations were further complemented 30 with information elicited from koala experts, who were immersed in 360-degree images of 31 the study area. The experts were asked to state the probability of observing a koala at sites 32 they viewed and to assign each probability a confidence rating. We fit logistic regression 33 models to the ground survey data and the ground plus thermal-imagery survey data and a beta 34 regression model to the expert elicitation data. We then combined parameter estimates from 35 the expert-elicitation model with those from each of the survey models to predict koala 36 presence and absence in the study area. The model that combined the ground, thermal-37 imagery and expert-elicitation data substantially reduced the uncertainty around parameter 38 estimates and increased the accuracy of classifications (koala presence vs absence), relative 39 to the model based on ground-survey data alone. Our findings suggest that data elicited from 40 experts using virtual reality technology can be combined with data from other emerging 41 technologies, such as airborne thermal-imagery, using traditional statistical models, to 42 increase the information available for species distribution modelling and the conservation of 43 vulnerable and protected species. Introduction 45In the face of unprecedented biodiversity loss, critical decisions are needed on the 46 conservation of vulnerable and protected species [1,2]. Unfortunately, information is seldom 47 available or dense enough in space and time to effectively inform those decisions [3].48 Monitoring programs often rely on observational records of species collected during ground 49 surveys. However, ground-based detection of vulnerable and protected species is difficult, 50 particularly when species are rare or elusive, and information may be biased towards single 51 or few individuals (e.g. radio-collared animals) or sites with high abundance [4,5].52 Furthermore, monitoring large areas using traditional ground-survey methods is logistically 53 and financially infeasible, and while professional monitoring may be time consuming and 54 expensive, volunteer data may be biased and of questionable quality [6,7]. These issues all 55 contribute towards the sparse data problem. 56Emerging technologies provide an opportunity to increase the spatial and temporal 57 coverage of data,...

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“…To date, research based on microsatellite markers has defined the genetic diversity and divergence of koala populations in Queensland, particularly SEQ (Fowler et al, 2000;Houlden et al, 1996c;Lau et al, 2014;Lee et al, 2010;Lee et al, 2013b;Sherwin et al, 2000). In 2010, a comprehensive study of in situ koalas in SEQ (n= 512) determined that genetic diversity is relatively high (HE= 0.69-0.73) within koala colonies in the threatened areas of SEQ (Lee et al, 2010), although by 2013, the same wild koala colonies had decreased in heterozygosity (HE= 0.55-0.67) (Lee et al, 2013).…”

Section: The Assessment Of Individual and Population Genetic Variationmentioning

confidence: 99%

“…determined that there was a substantial amount of genetic diversity (HE= 0.69-0.73) remaining within koala populations in the threatened areas of SEQ (Lee et al, 2010), although by 2013, the same wild koala colonies had decreased in heterozygosity (HE= 0.55-0.67) (Lee et al, 2013b). Further analysis of koalas in the Gold Coast region of SEQ was conducted in 2015, which used the same microsatellite markers to allow for a direct comparison and identified that the koala populations tested maintained a high level of heterozygosity (HE= 0.71-0.73) (Seddon et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Genetic analysis of koalas has primarily been conducted using microsatellite techniques, however, SNP technology is now available to perform a more comprehensive population analyses (Burgess, 2018;Cui et al, 2015;Fowler et al, 2000;Houlden et al, 1996c;Johnson et al, 2018;Lau et al, 2014;Lee et al, 2010;Lee et al, 2013b;Sherwin et al, 2000). The earlier studies on genetic diversity in SEQ koalas were based on only six microsatellite markers, and consequently, improvements in genetic analysis based on a larger number of genetic markers may now provide a more comprehensive analysis.…”

Section: Introductionmentioning

confidence: 99%

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The establishment of a Living Genome Resource Bank utilising genetic analysis and assisted breeding technology: a case study on the koala (Phascolarctos cinereus)

Schultz¹

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Genetic diversity in natural and introduced island populations of koalas in Queensland

Cited by 22 publications

References 50 publications

Koala Retrovirus Diversity, Transmissibility, and Disease Associations

Koala Retrovirus Diversity, Transmissibility, and Disease Associations

Using virtual reality and thermal imagery to improve statistical modelling of vulnerable and protected species

The establishment of a Living Genome Resource Bank utilising genetic analysis and assisted breeding technology: a case study on the koala (Phascolarctos cinereus)

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