Trans-species polymorphism of class IIMhc loci in danio fishes

Graser, Robert T.; Ó'hUigín, Colm; Vincek, Vladimir; Meyer, Axel; Klein, Jan

doi:10.1007/bf02602655

Cited by 68 publications

(12 citation statements)

References 49 publications

(19 reference statements)

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“…Similarly to many previous studies performed on fish species (e.g. [36], [70]–[71]), we confirmed the trans-species evolution of MHC IIB genetic polymorphism in P. toxostoma and C. nasus , i.e. one DAB3 -like allele ( Pctn-DAB3* 34) was shared between two species sampled in allopatric populations (however, only one allopatric population was sampled per species because of the protected status of P. toxostoma in southern France).…”

Section: Discussionmentioning

confidence: 74%

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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Section: Discussionmentioning

confidence: 74%

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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“…In mammals, MHC polymorphisms are maintained over long periods of time by balanced selection or positive selection at the non-synonymous sites specifying the PBR of the MHC [7]. The ratio between non-synonymous and synonymous substitutions in PBR sites of MHC IIB exon2 genes is greater than 1 (Table 3), as would be expected if the locus were evolving under a condition of balanced selection [58].…”

Section: Discussionmentioning

confidence: 99%

MHC polymorphism and disease resistance to vibrio anguillarum in 8 families of half-smooth tongue sole (Cynoglossus semilaevis)

Chen

Liu

et al. 2011

BMC Genet

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BackgroundGenes in the major histocompatibility complex (MHC) have a critical role in both the innate and adaptive immune responses because of their involvement in presenting foreign peptides to T cells. However, the nature has remained largely unknown.ResultsWe examined the genetic variation in MHC class IIB in half-smooth tongue sole (Cynoglossus semilaevis) after challenge with vibrio anguillarum. Two thousand and four hundred fry from 12 half-smooth tongue sole families were challenged with Vibrio anguillarum. To determine any association between alleles and resistance or susceptibility to V. anguillarum, 160 individuals from four high-resistance (HR, < 40.55% mortality) families and four low-resistance (LR, > 73.27% mortality) families were selected for MHC IIB exon2 gene sequence analysis. The MHC IIB exon2 genes of tongue sole displayed a high level of polymorphism and were discovered at least four loci. Meanwhile, the dN/dS [the ratio of non-synonymous (dN) substitutions to synonymous (dS) substitutions] in the peptide-binding region (PBR) was higher than that in the non-peptide-binding region (non-PBR). Eighty-eight alleles were discovered among 160 individuals, and 13 out of 88 alleles were used to analyze the distribution pattern between the resistant and susceptible families. Certain alleles presented in HR and LR with a different frequency, while other alleles were discovered in only the HR or LR families, not both. Five alleles, Cyse-DBB*6501, Cyse-DBB*4002, Cyse-DBB*6102, Cyse-DBB*5601 and Cyse-DBB*2801, were found to be associated with susceptibility to V. anguillarum with a frequency of 1.25%, 1.25%, 1.25%, 1.25% and 2.5% in the HR families, and 35%, 33.75%, 27.5%, 16.25%, 15% in the LR families (p < 0.01, 0.01, 0.01, 0.01, 0.01), respectively. Four alleles, Cyse-DBB*3301, Cyse-DBB*4701, Cyse-DBB*6801 and Cyse-DBB*5901, were found to be associated with resistance to V. anguillarum, with a frequency of 13.75%, 11.25%, 11.25%, 8.75% in the HR families and 1.25%, 1.25%, 1.25%, 1.25% and 1.25% in the LR families (p < 0.01, 0.05, 0.05 and p = 0.064), respectively.ConclusionsElucidation of the role of MHC II B genes in half-smooth tongue sole should prove to be helpful to the in-depth development of marker-assisted selective breeding in half-smooth tongue sole.

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“…The Danio spp. has been interchangeably identified as D. malabaricus [2,[35][36][37] and D. aequipinnatus [38][39][40], as distinct species [41], and declared to be synonymous [42]. Moyle & Senanayake [16] and Wickramanayake & Moyle [32] specified D. malabaricus as deep-bodied species that inhabiting fast-flowing hill streams.…”

Section: Taxonomic Discrepanciesmentioning

confidence: 99%

Fish Assemblage Structure of Two Contrasting Stream Catchments of the Mahaweli River Basin in Sri Lanka: Hallmarks of Human Exploitation and Implications for Conservation

Sumith¹

2011

TOCONSBJ

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Patterns of fish community composition in the Mahaweli ichthyological region of Sri Lanka were examined in agricultural tributaries of the Uma-oya catchment of the upper Mahaweli River in comparison to more pristine streams in a nature reserve in the Amban-ganga catchment. The Uma-oya catchment shows characteristics commonly observed in extensive agricultural exploitation such as impaired water quality and altered riparian vegetation. The most abundant fish species in the two regions were Garra ceylonensis, Devario malabaricus, and Rasbora daniconius, although their relative abundance differed between sites. G. ceylonensis and Neomacheilus notostigma were the only endemic fish species in common but the latter has been extremely depauperate. Endemism is higher in the reference sites (62.5%) than agricultural sites (ca. 25%); some of the reference streams showed greater diversity with unique fish species and a few species that have not been recorded previously in the catchment. The ichthyofaunal similarity between two catchments was 39% and fish species diversity was negatively correlated with stream gradients (Pearson correlation (-0.630); r 2 = 39.6% p = 0.028). Species density and biomass of G. ceylonensis and D. malabaricus were positively associated with some water quality parameters. The presence of exotic fish species were amongst the primary discriminants between human exploited and least-exploited (reference) streams. The possible negative impact of exotic Oreochromis niloticus (Nile tilapia) on indigenous G. ceylonensis is highlighted. This paper provides impetus for making several hypotheses for sustainability of stream fish assemblages in highly exploited agricultural catchments in Sri Lanka.

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Trans-species polymorphism of class IIMhc loci in danio fishes

Cited by 68 publications

References 49 publications

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

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

MHC polymorphism and disease resistance to vibrio anguillarum in 8 families of half-smooth tongue sole (Cynoglossus semilaevis)

Fish Assemblage Structure of Two Contrasting Stream Catchments of the Mahaweli River Basin in Sri Lanka: Hallmarks of Human Exploitation and Implications for Conservation

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