作　　者： ; ;

机构地区： 安徽师范大学生命科学学院

出　　处： 《生命科学研究》 2007年第3期258-262,272,共6页

摘　　要： 在基因组水平上,比较分析了已登录GenBank的19种龟鳖类线粒体全基因组的结构特征.结果表明:1)除平胸龟、扁陆龟外,其余17种龟鳖类线粒体基因组结构、基因排列顺序均与典型的脊椎动物相似,显示龟鳖类线粒体基因组在进化上十分保守:2)19种龟鳖类线粒体全基因组和各部分的碱基组成均表现出高AT、低G含量的偏向,在控制区中表现尤为明显:3)除中华鳖和白腹摄龟外,其余种类的某些蛋白编码基因中都存在一个或多个额外插入的核苷酸:4)除侧颈龟亚目的非洲侧颈龟外,其余18种曲颈龟线粒体DNA的"WANCY"区中都存在轻链复制起始点(OL),且它们的二级结构、核苷酸组成高度保守,推测该结构可能是曲颈龟亚目的一个共同特征:5)部分龟鳖类线粒体基因组控制区3′端存在大片段(200￣450 bp)的重复序列,某些龟鳖类中有由(AT)构成的微卫星序列,并且这些拷贝序列在种间表现出一定的差异,其可作为特异的分子标记,对于龟鳖类动物系统学的研究、亲缘关系的鉴定、物种多样性的保护和研究等方面具有重要的参考价值. The features of mitochondrial（mt） genomes of 19 turtles were compared and analyzed. In most of the turtles with the exception of Platysternon megacephalum and Malacochersus tornieri, the genome organization and gene order were similar to the typical vertebrate. The nucleotide compositions of the whole mt genome and different parts showed the bias of higher AT and lower G contents in the 19 turtles. Except Pelodiscus sinensis and Cyclemys atripons, one or a few extra nucleotides were found in some protein-coding genes of other known turtles. The light-strand replication origin （OL） was located inside WANCY region of all the 18 cryptodiran turtles, but contrasts with its apparent disappearance from the side-necked turtle （Pelomedusa subrufa）, which might be a common characteristic of Cryptodires. A large number of tandem repeats （containing microsatellites composed of AT） were presented at the 3＇end of the control regions in some reported turtles, furthermore, constitutions and numbers of these tandem units reflect differences in different species. The findings might be regarded as special molecular markers and applied to the molecular phylogenetics of turtles, the genetic relationship identification, as well as the conservation and study on species diversity.

关 键 词： 种龟鳖类 线粒体全基因组 基因组结构 控制区 串联重复序列

领　　域： [生物学]