Characterization of MHC class Ⅱ A genes in Hainan Eld's deer(Cervus eldi hainanus)

The major histocompatibility complex(MHC) genes play pivotal roles in the immune system of vertebrates against antigens.They are also significant indicators of genetic structure,and are vital to species-level population viability analyses and disease risk assessments.In this study,two DRA and two DQA sequences were isolated from Hainan Eld's deer(Cervus eldi hainanus) using rapid amplification of cDNA ends(RACE) and single-strand conformation polymorphism-heteroduplex(SSCP-HD) analysis.Nucleotide sequence analysis revealed large differences between the two DQA sequences,especially in their exon 2 regions,but only minimal differences between the variants of the DRA gene.Comparison of the predicted amino acid sequences of the Ceel-MHC class Ⅱ A variants with those from six other species revealed that these molecules share high homology among ruminants.A phylogenetic tree of four class Ⅱ A sequences from Hainan Eld's deer and the other species placed the newly identified DQA and DRA genes on two distinct branches(100%-supportively),and further divided the two DQA sequences into 98%-supportive DQA1 and 99%-supportive DQA2 clusters,respectively.Therefore,this study identified monomorphic Ceel-DQA1 and Ceel-DQA2 genes,and one dimorphic Ceel-DRA gene from Hainan Eld's deer.

The major histocompatibility complex （MHC） genes play pivotal roles in the immune system of vertebrates against antigens. They are also significant indicators of genetic structure, and are vital to species-level population viability analyses and disease risk assessments. In this study, two DRA and two DQA sequences were isolated from Hainan Eld＇s deer （Cervus eldi hainanus） using rapid amplification of cDNA ends （RACE） and single-strand conformation polymorphism-heteroduplex （SSCP-HD） analysis. Nucleotide sequence analysis revealed large differences between the two DQA sequences, especially in their exon 2 regions, but only minimal differences between the variants of the DRA gene. Comparison of the predicted amino acid sequences of the Ceel-MHC class II A variants with those from six other species revealed that these molecules share high homology among ruminants. A phylogenetic tree of four class II A sequences from Hainan Eld＇s deer and the other species placed the newly identified DQA and DRA genes on two distinct branches （100%-supportively）, and further divided the two DQA sequences into 98%-supportive DQA1 and 99%-supportive DQA2 clusters, respectively. Therefore, this study identified monomorphic CeeI-DQA1 and CeeI-DQA2 genes, and one dimorphic Ceel-DRA gene from Hainan Eld＇s deer.