Identification of 48 full-length MHC-DAB functional alleles in miiuy croaker and evidence for positive selection.

摘要: Major histocompatibility complex (MHC) molecules play a vital role in the immune response and are highly polymorphic gene superfamily vertebrates. As molecular marker associated with polymorphism disease susceptibility/resistance, of MHC genes has been investigated many tetrapods teleosts. Most studies were focused on second exon, which encodes peptide-binding region (PBR) α1- or β1-domain, but few have examined full-length coding region. To comprehensive investigate gene, we identified 48 miiuy croaker (Miichthys miiuy) class IIB (Mimi-DAB) functional alleles from 26 individuals. All encode 34 amino acid sequences, high level was detected Mimi-DAB alleles. The rate non-synonymous substitutions (dN) occurred at significantly higher frequency than that synonymous (dS) PBR, this result suggests balancing selection maintains polymorphisms locus. Phylogenetic analysis based exon 2 sequences both showed clustered into two major groups. A total 19 positive selected sites after testing for selection, 14 predicted to be antigen-binding sites, most significant resistance. provides an important resource analyzing association between researching selective breeding enhanced