Zeng Wang, Xiaoping Zhou, Qingxian Lin, Wenzhen Fang, Xiaolin Chen.Wang WQ.Plos One, 2013. 8(9): e74185.

The major histocompatibility complex (MHC) is an excellent molecular marker for the studies of evolutionary ecologyand conservation genetics because it is a family of highly polymorphic genes that play a key role in vertebrateimmune response. In this study, the functional genes of MHC Class II B (DAB) were isolated for the first time in avulnerable species, the Chinese egret (Egretta eulophotes). Using a full length DNA and cDNA produced by PCRand RACE methods, four potential MHC DAB loci were characterized in the genome of this egret and all four wereexpressed in liver and blood. At least four copies of the MHC gene complex were similar to two copies of the minimalessential MHC complex of chicken, but are less complex than the multiple copies expressed in passerine species. InMHC polymorphism, 19 alleles of exon 2 were isolated from 48 individuals using PCR. No stop codons or frameshiftmutations were found in any of the coding regions. The signatures of positive selection detected in potential peptidebindingregions by Bayesian analysis, suggesting that all of these genes were functional. These data will provide thefundamental basis for further studies to elucidate the mechanisms and significance of MHC molecular adaptation invulnerable Chinese egret and other ardeids.