Long‐term survival of a urodele amphibian despite depleted major histocompatibility complex variation

Babik, Wiesław; Pabijan, Maciej; Arntzen, J. W.; Cogălniceanu, Dan; Durka, Walter; Radwan, Jacek

doi:10.1111/j.1365-294x.2008.04057.x

Cited by 59 publications

(97 citation statements)

References 69 publications

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“…Our results imply that a mixture of drift and selection, but primarily drift, may explain MHC as well as microsatellite diversity patterns in Sussex frog populations. This is in accord with a similar comparison made with crested newts Triturus cristatus across Europe, in which both microsatellites and MHC loci showed 'southern richness' and 'northern purity' (Babik et al, 2009). The overall correlation of inter-site F ST estimates between microsatellites and MHC implied a role for drift, but the stronger differentiation at MHC loci compared with microsatellites in urban populations may reflect an element of selection.…”

Section: Discussionsupporting

confidence: 88%

Larval fitness, microsatellite diversity and MHC class II diversity in common frog (Rana temporaria) populations

Zeisset

Beebee

2009

Heredity

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There is increasing interest in using functional rather than neutral loci to assess the genetic health of wild populations. We compared growth and survival of urban and rural frog larvae under three temperature regimes, to vary stress levels, and measured genetic diversities at nine microsatellites and at one major histocompatibility complex (MHC) class II locus. We found no significant differences between urban and rural frogs in larval survivorship, nor in microsatellite and MHC diversities. However, mean larval growth rates were significantly higher (by 4.5-18.9% according to temperature) in urban compared with rural populations. Microsatellite and MHC diversities were uncorrelated, though pairwise inter-site F ST estimates based on the two types of loci were correlated. MHC F ST estimates averaged about twice as high as those based on microsatellites. There was no evidence of isolation by distance with either marker. There were no correlations at the population level between any larval fitness attribute (growth rate or survival) and any diversity estimate (microsatellite or MHC). There was, however, a weak correlation at the sibship level between mean growth rate and microsatellite expected heterozygosity. MHC alleles varied among dying larvae and survivors, and in one case between urban and rural sites, with one allele being underrepresented in dying larvae and one allele only occurring in the rural sites. Drift was probably the primary cause of genetic population structure at both types of loci. The use of functional loci to assess population genetic health should focus on the roles of specific alleles as well as overall diversity.

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Section: Discussionsupporting

confidence: 88%

Larval fitness, microsatellite diversity and MHC class II diversity in common frog (Rana temporaria) populations

Zeisset

Beebee

2009

Heredity

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“…Though DRB genes usually display high diversity, in cases of small and isolated or bottlenecked populations, a lower variation is expected [52]. Similar results were found in other species such as northern elephant seals (Mirounga angustirostris) [53], great crested newt (Triturus cristatus) [54], and the black-footed rock-wallaby (Petrogale lateralis lateralis) [55]. Genetic drift is the reason for the reduced MHC variation in these populations because compared with balancing selection, which usually has a great influence on MHC genes, genetic drift becomes relatively stronger in small, isolated populations, leading to reduced variation at the MHC loci [56].…”

Section: Genetic Variation Of Drb In Golden Snub-nosed Monkeysupporting

confidence: 71%

“…First, three regions which encompassing putative ABS sites with a significantly positive (P<0.05) D value were identified in Tajima's D test across the exon 2 sequences (Figure 4), suggesting balancing selection exists on these regions [16,59]. Additionally, the sharing of MHC alleles among populations also indicates that MHC alleles may have been conserved by selection [54]. Second, random sites model analysis in PAML showed the existence of base selection in the maximum likelihood method.…”

Section: Balancing Selection and Recombinationmentioning

confidence: 97%

MHC II DRB variation and trans-species polymorphism in the golden snub-nosed monkey (Rhinopithecus roxellana)

Luo

Pan

2013

Chin. Sci. Bull.

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Genetic variation is generally believed to be important in studying endangered species' adaptive potential. Early studies assessed genetic diversity using nearly neutral markers, such as microsatellite loci and mitochondrial DNA (mtDNA), which are very informative for phylogenetic and phylogeographic reconstructions. However, the variation at these loci cannot provide direct information on selective processes involving the interaction of individuals with their environment, or on the capability to resist continuously evolving pathogens and parasites. The importance of genetic diversity at informative adaptive markers, such as major histocompatibility complex (MHC) genes, is increasingly being realized, especially in endangered, isolated species. Small population size and isolation make the golden snub-nosed monkey (Rhinopithecus roxellana) particularly susceptible to genetic variation losses through inbreeding and restricted gene flow. In this study, we compared the genetic variation and population structure of microsatellites, mtDNA, and the most relevant adaptive region of the MHC II-DRB genes in the golden snub-nosed monkey. We examined three Chinese R. roxellana populations and found the same variation patterns in all gene regions, with the population from Shennongjia population, Hubei Province, showing the lowest polymorphism among three populations. Genetic drift that outweighed balancing selection and the founder effect in these populations may explain the similar genetic variation pattern found in these neutral and adaptive genes.

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“…Although there are undoubtedly exceptions, these studies and others suggest that a high variability at MHC DRB coupled with low microsatellite diversity appears to be a relatively frequent occurrence in natural populations that are the subject of conservation concern because of small population size. Why this might be so has been the subject of considerable discussion and debate (Aguilar et al, 2004;van Oosterhout et al, 2006;Babik et al, 2009a).…”

Section: Patterns Of Mhc Diversitymentioning

confidence: 99%

Extensive variation at MHC DRB in the New Zealand sea lion (Phocarctos hookeri) provides evidence for balancing selection

et al. 2013

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Marine mammals are often reported to possess reduced variation of major histocompatibility complex (MHC) genes compared with their terrestrial counterparts. We evaluated diversity at two MHC class II B genes, DQB and DRB, in the New Zealand sea lion (Phocarctos hookeri, NZSL) a species that has suffered high mortality owing to bacterial epizootics, using Sanger sequencing and haplotype reconstruction, together with next-generation sequencing. Despite this species' prolonged history of small population size and highly restricted distribution, we demonstrate extensive diversity at MHC DRB with 26 alleles, whereas MHC DQB is dimorphic. We identify four DRB codons, predicted to be involved in antigen binding, that are evolving under adaptive evolution. Our data suggest diversity at DRB may be maintained by balancing selection, consistent with the role of this locus as an antigen-binding region and the species' recent history of mass mortality during a series of bacterial epizootics. Phylogenetic analyses of DQB and DRB sequences from pinnipeds and other carnivores revealed significant allelic diversity, but little phylogenetic depth or structure among pinniped alleles; thus, we could neither confirm nor refute the possibility of trans-species polymorphism in this group. The phylogenetic pattern observed however, suggests some significant evolutionary constraint on these loci in the recent past, with the pattern consistent with that expected following an epizootic event. These data may help further elucidate some of the genetic factors underlying the unusually high susceptibility to bacterial infection of the threatened NZSL, and help us to better understand the extent and pattern of MHC diversity in pinnipeds.

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Long‐term survival of a urodele amphibian despite depleted major histocompatibility complex variation

Cited by 59 publications

References 69 publications

Larval fitness, microsatellite diversity and MHC class II diversity in common frog (Rana temporaria) populations

Larval fitness, microsatellite diversity and MHC class II diversity in common frog (Rana temporaria) populations

MHC II DRB variation and trans-species polymorphism in the golden snub-nosed monkey (Rhinopithecus roxellana)

Extensive variation at MHC DRB in the New Zealand sea lion (Phocarctos hookeri) provides evidence for balancing selection

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