RAJAKARUNA, R.S.*; BROWN, J.A.; KAUKINEN, K.; MILLER, K.M.: MHC genes influence the kin recognition in juvenile Atlantic salmon

Several animal species have the ability to recognize kin from unrelated conspecifics. In salmonids, juveniles can discriminate between unfamiliar kin and unrelated individuals. They probably use a phenotype matching mechanism for the recognition, which involves comparison of a conspecific’s phenotypic characteristics to a learned or genetically dictated recognition template. We studied whether the kin recognition in juvenile Atlantic salmon, Salmo salar is influenced by the major histocompatibility complex (MHC). We analysed the highly polymorphic peptide-binding region of MHC class II gene using the polymerase chain reaction (PCR) in combination with denaturing gradient gel electrophoresis (DGGE) to determine genetic variation at the B1 locus. We used the information about the MHC genotype of kin and non-kin groups to study their discrimination abilities. When the juveniles had a choice between kin sharing same alleles and kin sharing no alleles, they preferred kin sharing alleles. Juveniles also preferred non-kin sharing same alleles to non-kin sharing no alleles. This suggests that MHC influences kin recognition in juvenile Atlantic salmon. Juveniles choosing kin sharing no alleles over non-kin sharing no alleles indicates that the rest of the genome except for MHC also has an influence. When we tested the relative importance of MHC, compared to the rest of the genome, juveniles could not discriminate kin sharing no alleles and non-kin sharing either one or two alleles. This indicates that MHC is as potent as the rest of the genome in producing discriminable body odours.