摘要: 利用牛DRB3特异性引物(LA31和LA32),通过聚合酶链式反应(PCR)、单链构象多态性(SSCP)以及克隆测序技术,从12只黄麂个体中共获得20个DRB第二外显子等位基因,其中6个个体具有3～4个等位基因,提示利用该引物从黄麂中至少可以扩增出2个DRB位点。所有序列均无插入、缺失和终止密码子。基于序列比对(与牛DRB3和鹿科DRB基因同源性非常高),以及所检测到的氨基酸变异位点主要位于抗原结合区,推测本文所获得的黄麂序列为表达的、且具有重要功能的DRB位点。抗原结合区氨基酸位点的非同义替换(dN)显著大于同义替换(dS)(P<0.01),说明历史上黄麂DRB基因经历过正选择作用。CODMEL程序中的模型M7和M8似然比检测(Likelihood ratio test,LRT)结果同样支持上述推论。进一步利用经验贝叶斯法准确地检测出6个受正选择作用的氨基酸位点(位点11、37、61、67、71、86),其中的5个位点位于PBR区。因此,正选择作用可能是维持黄麂DRB基因多态性的主要机制之一。基于DRB外显子2序列利用邻接法(NJ)构建了部分偶蹄动物系统发生关系,在NJ树上,黄麂DRB基因与其它鹿科动物DRB基因呈镶嵌式分布,提示跨物种进化是维持黄麂DRB基因多态性的另一重要机制。此外,黄麂两个等位基因(Mure-DRB1和Mure-DRB11)和马鹿的两个等位基因(Ceel-DRB34和Ceel-DRB46)与牛科的等位基因构成一个独立的进化枝,说明黄麂和马鹿的某些DRB基因具有非常古老的谱系。
摘要: An undetermined animal specimen of Cervidae deposited in the Museum of Anhui Normal University has many characteristics similar to male sika deer excect for both buckhorns without any ramus. In the present study,a partial sequence of mitochondrial DNA cytochrome b gene was cloned and sequenced,then submitted to NCBI for blast. The results showed that the target sequence of the examined animal had great similarity to that of sika deer with the sequence difference between the two animals only 0.9%,which was inside of the range of cytochrome b gene sequence variation within species (0-3%). Similarly,phylogenetic analysis based on the the cytochrome b gene fragment for 11 deer using Neibor-joining method also indicated that the animal was highly related to sika deer. Therefore,the animal was identified as an individual of sika deer with morphological variation in the buckhorn. Because the animal was from Jing county Anhui Province,and given the current distribution of sika deer in China,the specimen was tentatively identified as Cervus nippon pseudaxis.