Evolutionary mechanisms: Implications of MHC-mediated behaviours on social interactions and their contribution to population divergence during speciation
Zusammenfassung der Projektergebnisse
Previous laboratory studies had shown that juvenile perch are able to discriminate kin from non kin and conspecifics of the same from a foreign subpopulation via odour cues. The main goal of this project was to investigate the potential role of major histocompatibility complex (MHC) genes in social behaviours including kin and population recognition but also mate choice in perch. Variability of MHC class II (MHII) alleles was very high and a minimum of eight loci were found. The 3-dimensional structure of the MHII ß1 domain in perch showed the characteristic MHC fold as known from other vertebrates, and positively selected codons in the putative antigen binding site of perch were found. We developed a new method based on reference strand conformation analysis (RSCA) for perch that allowed individual genotyping of MHII alleles. After this methodological approach, we tested perch in behavioural choice tests for population recognition, a preference of MHC similar individuals, and for MHC-mediated mate choice. No indications were found that self-referent phenotype matching based on allele similarity at MHII is used to discriminate kin. However, we showed that perch significantly preferred conspecifics of the own versus the foreign population. Although we found unique MHII alleles in both populations tested, the overall MHII allele pattern was not significantly different. Based on these findings it remains doubtful that perch use population specific MHII alleles to discriminate between populations. In respect to MHC-mediated mate choice, no indications for inbreeding avoidance was found as mating appeared random in respect to MHII similarity or dissimilarity between mating partners. However, our methodological possibilities so far did not allow to test whether partners choose their mates in order to increase the heterozygosity of their offspring at the peptide binding region of the MHC, which would provide them with better defence against parasites and pathogens. Thus no final conclusion on the role of MHC in mate choice of perch can be drawn. To sum up, we found high variability of the MHC but our tests did not indicate so far that MHC genes play any role during social behaviours such as kin recognition, population recognition or mate choice in perch.
Projektbezogene Publikationen (Auswahl)
- (2009) Diversity and evolution of MHII beta genes in a non-model percid species - the Eurasian perch (Perca fluviatilis L.). Molecular Immunology 46, 3399-3410
Michel C, Bernatchez L, Behrmann-Godel J
- (2012) Genotyping MHC classIIB in non-model species by reference strand-mediated conformational analysis (RSCA). Conservation Genetics Resources
Oppelt, C Behrmann-Godel J
(Siehe online unter https://doi.org/10.1007/s12686-012-9655-0)
