Publication details
THE ROLE OF MHC DIVERSITY IN FISH VIGOUR, IMMUNOCOMPETENCE AND PARASITE SELECTION IN COMMON BREAM (ABRAMIS BRAMA L.)
| Authors | |
|---|---|
| Year of publication | 2006 |
| Type | Article in Proceedings |
| Conference | XIth International Congress of Parasitologists |
| MU Faculty or unit | |
| Citation | |
| Field | Zoology |
| Keywords | MHC DIVERSITY ; IMMUNOCOMPETENCE; PARASITE; COMMON BREAM |
| Description | The highly polymorphic MHC (major histocompatibility complex) genes play a central role in controlling immunological self and non-self recognition, and they permit to recognize the foreign antigens derived from pathogens or parasites. Two hypotheses explaining the factors maintaining the extensive MHC polymorphism have been proposed: parasite-driven selection and MHC-based mating preferences. In our study we investigated the patterns of MHC diversity in males of common bream collected during breeding season and tested whether MHC diversity is related to the fish condition status, immunocompetence measured by the spleen size, sexual ornamentation (the expression of breeding tubercles) and diversity of metazoan parasites. Two allelic groups DAB1 and DAB3 were recognized using the nucleotide similarity and phylogenic analyses. The individual males expressed one of the following types of alleles (i) one DAB1 allele, (2) two alleles of single lineage (DAB1 or DAB3) or (3) two allele of different lineages (DAB1 and DAB3). The presence of any special DAB allele was not associated with parasite presence. The nucleotide diversity in individuals expressing a single type of alleles increased with the abundance of Dactylogyrus spp. (Monogenea) and Ergasilus sp.(Crustacea). Moreover, the higher level of sexual ornamentation was found in fish expressing two alleles of a single lineage. The negative relationship was found between spleen size and nucleotide variability in this group of individuals suggesting an association between MHC and immunocompetence. Those results could support a role of MHC as a candidate of “good genes”. We found that MHC diversity reflects a status of host vigour measured by condition factor when fish with combined type of DAB alleles had higher condition factor and are less ornamented. MHC variability in the individuals expressing the combined type of alleles was not associated by parasites or immunocompetence. Thus, the expression of different allelic lineages seems to be advantageous for fish males. |
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