MHC class II β genes in the endangered Hainan Eld's deer (Cervus eldi hainanus).

Contrary to neutral markers, the major histocompatibility complex (MHC) can reflect the fitness and adaptive potential of a given species due to its association with the immune system. For this reason, the use of MHC in endangered wildlife management has increased greatly in recent years. Here, we isolated complementary DNA (cDNA) and genomic DNA (gDNA) sequences to characterize the MHC class II β genes in Hainan Eld's deer (Cervus eldi hainanus), a highly endangered cervid, which recovered from a severe population bottleneck consisting of 26 animals. Analysis of 7 individuals revealed the presence of 3 DRB and 3 DQB putatively functional gDNA sequences. The Ceel-DRB and DQB sequences displayed high variability in exon 2, and most nonsynonymous substitutions were detected in this region. Phylogenetic analysis indicated that trans-species evolution of MHC class II β might occur in the Cervinae subfamily. Comparison of the number of sequences between gDNA and cDNA revealed that all sequences isolated from the genome were detectable in the cDNA libraries derived from different tissues (including the liver, kidney, and spleen), suggesting none of these sequences were derived from silent genes or pseudogenes. Characterization of the MHC class II β genes may lay the foundation for future studies on genetic structure, mate choice, and viability analysis in Hainan Eld's deer.