MHC screening for marsupial conservation: extremely low levels of class II diversity indicate population vulnerability for an endangered Australian marsupial

Smith, Steve; Belov, Katherine; Hughes, Jane

doi:10.1007/s10592-009-0029-4

Cited by 14 publications

(8 citation statements)

References 62 publications

(69 reference statements)

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“…The WBB samples yielded fewer SNPs (n=1752) than the other species, despite similar sequencing success and locus discovery, suggesting lower average genetic diversity in this species. This is in agreement with previous studies showing very low genetic diversity in WBBs using microsatellite, mitochondrial (Smith and Hughs, 2008), and MHC (Smith et al, 2010) markers.…”

Section: Sequencing Resultssupporting

confidence: 93%

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Long-term genetic consequences of mammal reintroductions into an Australian conservation reserve

White

Moseby

Thomson

et al. 2018

Biological Conservation

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Section: Sequencing Resultssupporting

confidence: 93%

“…Allelic richness ranged from 1.13 (Faure Island founder WBBs) to 1.34 (Arid Recovery descendant bettongs). The WBBs had the lowest genetic diversity of the four species, again consistent with previous studies (Smith and Hughes, 2008;Smith et al, 2010).…”

Section: Genetic Diversity and Inbreedingsupporting

confidence: 91%

Long-term genetic consequences of mammal reintroductions into an Australian conservation reserve

White

Moseby

Thomson

et al. 2018

Biological Conservation

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“…Concerning the populations of different endangered species, low genetic diversity of MHC especially due to a bottleneck effect has been shown (e.g. [3], [62]), suggesting that such species may be exposed to increased vulnerability to novel pathogens. However, P. toxostoma , a fish with protected status in southern France, expressed similar total numbers of MHC IIB allelic variants at the population level when compared to the populations of invasive C. nasus .…”

Section: Discussionmentioning

confidence: 99%

Genomic Porosity between Invasive Chondrostoma nasus and Endangered Endemic Parachondrostoma toxostoma (Cyprinidae): The Evolution of MHC IIB Genes

et al. 2013

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Two cyprinid species, Parachondrostoma toxostoma, an endemic threatened species, and Chondrostoma nasus, an invasive species, live in sympatry in southern France and form two sympatric zones where the presence of intergeneric hybrids is reported. To estimate the potential threat to endemic species linked to the introduction of invasive species, we focused on the DAB genes (functional MHC IIB genes) because of their adaptive significance and role in parasite resistance. More specifically, we investigated (1) the variability of MHC IIB genes, (2) the selection pattern shaping MHC polymorphism, and (3) the extent to which trans-species evolution and intergeneric hybridization affect MHC polymorphism.In sympatric areas, the native species has more diversified MHC IIB genes when compared to the invasive species, probably resulting from the different origins and dispersal of both species. A similar level of MHC polymorphism was found at population level in both species, suggesting similar mechanisms generating MHC diversity. In contrast, a higher number of DAB-like alleles per specimen were found in invasive species. Invasive species tended to express the alleles of two DAB lineages, whilst native species tended to express the alleles of only the DAB3 lineage. Hybrids have a pattern of MHC expression intermediate between both species. Whilst positive selection acting on peptide binding sites (PBS) was demonstrated in both species, a slightly higher number of positively selected sites were identified in C. nasus, which could result from parasite-mediated selection. Bayesian clustering analysis revealed a similar pattern of structuring for the genetic variation when using microsatellites or the MHC approach. We confirmed the importance of trans-species evolution for MHC polymorphism. In addition, we demonstrated bidirectional gene flow for MHC IIB genes in sympatric areas. The positive significant correlation between MHC and microsatellites suggests that demographic factors may contribute to MHC variation on a short time scale.

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“…In the case of non-carnivore mammals, heterozygosity of the DRB gene in a population of the striped mouse ( Rhabdomys pumilio ), has been shown to influence infection status [21]. A low level of diversity at the DAB locus (an MHC class II gene in marsupials) in the western barred bandicoot ( Perameles bougainville ) may influence its vulnerability against novel pathogens [22]. …”

Section: Introductionmentioning

confidence: 99%

MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

et al. 2012

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BackgroundThe major histocompatibility complex (MHC) genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus). Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus) from 12 local populations.ResultsAmong 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes) and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected.ConclusionsThe low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other endangered mammalian species. This result suggests that the Japanese black bears may also retain more potential resistance against pathogens than other endangered mammalian species. To prevent further decline of potential resistance against pathogens, a conservation policy for the Japanese black bear should be designed to maintain MHC rare variants in each local population.

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MHC screening for marsupial conservation: extremely low levels of class II diversity indicate population vulnerability for an endangered Australian marsupial

Cited by 14 publications

References 62 publications

Long-term genetic consequences of mammal reintroductions into an Australian conservation reserve

Long-term genetic consequences of mammal reintroductions into an Australian conservation reserve

Genomic Porosity between Invasive Chondrostoma nasus and Endangered Endemic Parachondrostoma toxostoma (Cyprinidae): The Evolution of MHC IIB Genes

MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

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