Parasites, MHC allelic diversity and microsatellite variability among European populations of chub (Leuciscus cephalus Linnaeus, 1758)
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| Year of publication | 2007 |
| Type | Appeared in Conference without Proceedings |
| MU Faculty or unit | |
| Citation | |
| Description | Major histocompatibility complex (MHC) is the most polymorphic gene cluster in vertebrate genome; the high level of polymorphism is maintained by pathogen or parasite driven balancing selection. It is hypothesized that the populations with high genetic variability in MHC will have more diverse array of parasites following the prediction that the parasite diversity represents a selective force driving the diversification of the MHC genes. In this study, the potential link between parasite diversity and MHC class IIB genes variability was investigated in selected populations of chub (Leuciscus cephalus) collected in different European river basins. Molecular techniques (SSCP, RT-PCR, PCR, cloning and sequencing) were used to analyze variability of the exon 2 of the DAB genes (MHC IIB class), which encodes the beta1 domain of the MHC class II molecules; exon 2 is considered as the most polymorphic fragment of these molecules. Some fish individuals expressed only DAB1 or DAB3 alleles, other ones expressed both of them. The minimum number of alleles per fish was one and maximum number was five. All identified parasite species represent 8 higher metazoan parasite taxa: Monogenea, Crustacea (parasitic Copepoda), Mollusca, Hirudinea, Digenea, Acantocephala, Nematoda and Cestoda. Chub harboured more ectoparasite than endoparasite species. The highest values of abundance, prevalence and mean intensity of infection were observed for monogenean species. The microsatellite variability was also analyzed using microsatellite loci as a neutral marker to estimate the role of selectively neutral processes on MHC polymorphism and parasitism; and to analyze how geographic origin and history have influenced the degree of genetic diversity. The analysis revealed the relationship between parasite diversity and MHC variability; populations with high parasite species diversity have also high degree of MHC class IIB genes diversity. |
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