中国部分猪种SLA-DQB外显子2遗传多样性  

The Genetic Diversity of the Second Exon of SLA-DQB in Some Chinese Native Pigs

作　　者：李华[1] 张亚平[1] 邱祥聘[2] 

机构地区：[1]中国科学院昆明动物研究所细胞与分子进化重点实验室 [2]四川农业大学动物科技学院,雅安625014

出　　处：《遗传》2005年第2期173-180,共8页Hereditas（Beijing)

基　　金：国家重点基础研究发展规划项目资助(编号:G20000161)~~

摘　　要：运用 PCR SSCP 和克隆测序对中国部分猪种的 SLA DQB 基因外显子 2 的多态性分析表明:有功能的DQB 基因有68个新等位基因,假基因(SLA DXB )等位基因有5个。各等位基因的数量分布极其不平衡,而且许多品种都表现出共享等位基因。9个主要等位基因中, C08广泛分布在中国猪种的 6 大地方类型 11 个品种及云南和四川野猪中,它为中国猪种特有的共享等位基因,占总数的 55.10%。在单一的个体中拥有 5 条以上序列,说明SLA DQB 基因座在某些品种中拷贝数为3个。SLA DQB 外显子2的等位基因核苷酸和氨基酸多态变异位点分别高达81个和49个,等位基因多样度(H=0.889)以及核苷酸多样度(Pi=0.047)都很高,总体表现为β折叠区的Pi值均高于α螺旋区。综合分析表明华南型、西南型猪H 和Pi 均较高,高原型的藏猪最低。类群内遗传距离排序与Pi 值高低排序一样,可见各地方类型中核苷酸替换的差异正比于核苷酸多样度。类群间遗传距离比较,江海型与华北型间的距离最大,而华中型和高原型间的遗传距离最小。Polymorphism of the second exon of SLA-DQB genes in some Chinese native pigs was investigated employing PCR-SSCP analysis and DNA cloning sequencing. Combined with the sequences in GenBank, 73 new alleles were gained, among them function alleles of SLA-DQB were sixty-eight, five alleles of pseudogene (SLA-DXB) were gained. There were disequilibrium distribution of the alleles in all breeds, the same allele was shared by most breeds. C08 allele existed in 11 breeds of six groups and in the wild pigs of Yunnan and Sichuan provinces, and its frequency reached 55.10%. More than five sequences were found in each individual, suggesting duplication in these loci examined, there were three copies about SLA-DQB genes. The variable sites based on nucleotide and amino acids reached to eighty-one and forty-nine, respectively. The values of allelic diversity (H=0.889) and the nucleotide diversity (Pi=0.047) were revealed very high, for both values of H and Pi were higher in the β pleated sheet region than those in α helix region in Chinese native pigs. In general, values of H and Pi in Huanan pigs and Xinan pigs were higher, while those in Tibet pigs were lower. The genetic distance within group was shown the same order as that of Pi values, hence we concluded the different rate of nucleotide substitution was positively correlated with the degree of nucleotide diversity in Chinese domestic groups. The genetic distances detected of SLA-DQB gene between groups were as follows: the great genetic distance existed between the Jianghai and Huabei groups, and the smallest genetic distance existed between the Huazhong and Gaoyuan groups.

关 键 词：中国猪种 SLA-DQB 遗传多样性 

分 类 号：S828.8[农业科学—畜牧学]