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

Schultz, B.

doi:10.14264/uql.2019.897

Cited by 3 publications

(4 citation statements)

References 237 publications

(502 reference statements)

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“…First, the predicted magnitude of predicted genetic diversity loss was extensive and far exceeded the recently estimated 5.4%–6.5% overall vertebrate decline in genetic diversity since the industrial revolution (Leigh et al 2019). Second, a decrease in genetic diversity in koalas is known to carry negative fitness consequences including body condition, reproductive success and sperm quality (Schultz, 2019). Last, research has shown that genetic erosion combined with small population size are significant contributors to population extinction risk (Hohenlohe et al, 2021; Templeton et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

Evaluating the genetic consequences of population subdivision as it unfolds and how to best mitigate them: A rare story about koalas

et al. 2023

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The genetic consequences of the subdivision of populations are regarded as significant to long‐term evolution, and research has shown that the scale and speed at which this is now occurring is critically reducing the adaptive potential of most species which inhabit human‐impacted landscapes. Here, we provide a rare and, to our knowledge, the first analysis of this process while it is happening and demonstrate a method of evaluating the effect of mitigation measures such as fauna crossings. We did this by using an extensive genetic data set collected from a koala population which was intensely monitored during the construction of linear transport infrastructure which resulted in the subdivision of their population. First, we found that both allelic richness and effective population size decreased through the process of population subdivision. Second, we predicted the extent to which genetic drift could impact genetic diversity over time and showed that after only 10 generations the resulting two subdivided populations could experience between 12% and 69% loss in genetic diversity. Lastly, using forward simulations we estimated that a minimum of eight koalas would need to disperse from each side of the subdivision per generation to maintain genetic connectivity close to zero but that 16 koalas would ensure that both genetic connectivity and diversity remained unchanged. These results have important consequences for the genetic management of species in human‐impacted landscapes by showing which genetic metrics are best to identify immediate loss in genetic diversity and how to evaluate the effectiveness of any mitigation measures.

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Section: Discussionmentioning

confidence: 99%

Evaluating the genetic consequences of population subdivision as it unfolds and how to best mitigate them: A rare story about koalas

et al. 2023

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“…Another, more intensive approach to counteract genetic erosion is a genetic rescue or genetic restoration through the introduction of new genes, which can alleviate inbreeding and genetic load (decreased fitness of a population due to unfavorable alleles) and increase levels of genetic variation (Ralls et al, 2018; Weeks et al, 2011; Whiteley et al, 2015). This can be done through physical translocation of individuals from other populations or through assisted breeding technologies which have been successful for koalas (Johnston & Holt, 2014; Schultz, 2019b). While physical translocation is considered a primary tool for conservation management, it has proven difficult in several species (Ottewell et al, 2014; Weeks et al, 2011) and likely requires ongoing augmentation and supplementation to prevent genetic erosion in the long term.…”

Section: Discussionmentioning

confidence: 99%

“…There are also risks associated with physical translocation, the biggest ones for koalas being disease transmission (Waugh et al, 2016) and a non-adaptive specialized gut microbiome (Blyton et al, 2019). Most of these risks can be avoided with artificial insemination and recent advances toward a "Living Genome Resource Bank" for koalas show promising results that could facilitate the genetic rescue of koala populations (Schultz, 2019b). If the risk of outbreeding depression is low, and with a careful selection of the origin of the introduced individuals, Ralls et al (2018) state that genetic rescue would be better than inaction and could decrease the risk of extinction of genetically eroded populations.…”

Section: Implications For Managementmentioning

confidence: 99%

Genetic erosion detected in a specialist mammal living in a fast‐developing environment

Hohwieler

Villiers

Cristescu

et al. 2022

Conservat Sci and Prac

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Fragmentation of habitat is a major threat across a wide range of taxa. Subsequent effects include reduced population sizes and isolation of populations. Both can have detrimental consequences for populations as they increase the risk of genetic erosion. While it is critical to prevent and, if required, reverse genetic erosion, we often lack adequate data to assess whether and how much genetic erosion has occurred. Here, we present a genetic monitoring study where we investigated changes in genetic diversity and genetic patterns in a threatened, specialist mammal, the koala (Phascolarctos cinereus). Our study population inhabits an increasingly fragmented landscape and has experienced a sharp decline in population size within the past three decades. We used 1038 single nucleotide polymorphic loci (SNPs) to compare measures of genetic diversity between samples collected in 2018 and in 2006 (two generations prior) and investigated simultaneous changes in the environment. We found a decline in both heterozygosity and effective population size (N e ), and an increase in sub-structuring, average relatedness, and inbreeding (F IS ) alongside an increasingly threatening and more fragmented environment. Given the extent of genetic erosion in only two generations, we urge consideration for the implementation of mitigation measures for this population and for threatened populations in similar conditions. Our study further emphasizes the importance of effective management of at-risk populations including monitoring of genetic erosion.

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“…Firstly, the predicted magnitude of predicted genetic diversity loss was extensive and far exceeded the recently estimated 5.4-6.5% overall vertebrate decline in genetic diversity since the industrial revolution (Leigh et al 2018). Secondly, a decrease in genetic diversity in koalas is known to carry negative fitness consequences including body condition, reproductive success and sperm quality (Schultz 2019). Lastly, research has shown that genetic erosion, combined with small population size, are significant contributors to population extinction risk (Templeton et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Immediate and long-term genetic consequences of linear transport infrastructure: can fauna crossing mitigate its cost?

Frère

O'Reilly

Strickland

et al. 2022

Preprint

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Linear infrastructure stands as one of the main culprits of anthropogenically caused biodiversity decline. As it fragments landscapes, it ultimately results in a myriad of direct and indirect ecological consequences for wildlife. As transportation networks will continue to grow under increasing human population growth, biodiversity will continue to decline making the need to understand and mitigate their impact on species an urgent need for conservation worldwide. The implementation of mitigation measures to alleviate the barrier effect produced by linear transport infrastructure on local fauna is not new, and research has shown that their effectiveness has been shown to be influenced by their design, their placement and the biology of the impacted species. Our understanding of their effectiveness in preventing the longer-term impacts of linear transport infrastructure on habitat connectivity via gene flow, however, remains poorly understood. Here, we used a pre- and post-habitat fragmentation genetic dataset collected as part of an extensive Koala Management Program to ask questions about the immediate and predicted longer-term genetic consequences of linear transport infrastructure on the impacted species. Importantly, using forward migration simulations, we show that to preserve connectivity would need to result in around 20% of the population mixing to avoid long-term genetic drift. These results have important consequences for the management of species at the forefront of linear infrastructure. In particular, the study shows the importance of considering gene flow in our assessment of the effectiveness of fauna crossings.

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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)

Cited by 3 publications

References 237 publications

Evaluating the genetic consequences of population subdivision as it unfolds and how to best mitigate them: A rare story about koalas

Evaluating the genetic consequences of population subdivision as it unfolds and how to best mitigate them: A rare story about koalas

Genetic erosion detected in a specialist mammal living in a fast‐developing environment

Immediate and long-term genetic consequences of linear transport infrastructure: can fauna crossing mitigate its cost?

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