两栖动物线粒体基因组tRNA基因重复、丢失及其影响  

Influence of tRNA Gene Duplication and Loss within Amphibian Mitochondrial Genome

作　　者：夏云[1,2] 彭锐[1,3] 郑渝池[1] 曾晓茂[1] 

机构地区：[1]中国科学院成都生物研究所,成都610041 [2]中国科学院研究生院,北京100049 [3]四川大学生命科学学院,成都610064

出　　处：《应用与环境生物学报》2010年第6期822-827,共6页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(Nos.30870287;30900134);中国科学院知识创新工程项目(No.KSCX2-YW-Z-0906)资助~~

摘　　要：在脊椎动物线粒体基因组中,偶有tRNA基因重复或丢失事件发生,这些事件因与相应氨基酸转运密切关联而凸显重要.两栖类中,这些重复或丢失相对多样,可为相关研究提供良好素材.为了解这些事件对氨基酸对应的密码子使用偏好是否产生影响,本文引入统计方法,检测10种两栖类mtDNA蛋白编码基因相对的同义密码子使用度(RSCU),并特别设计将发生tRNA基因重复或丢失物种与其近缘群进行对比分析.结果显示,tRNA基因的重复对密码子使用偏好没有显著的影响,推测可能与突变积累的时限和mtDNA紧凑性有关.另外,tRNA基因丢失也未使相应氨基酸密码子使用偏好产生明显的改变.推测在两栖类中,"tRNA转入"和"tRNA反密码子摆动位点的超级摆动"可能是tRNA基因丢失的补偿方式.The duplication and loss of tRNA genes are rare to see in vertebrate mitochondrial genome（mtDNA）,while this phenomenon was found diversified in amphibian mtDNA.In order to understand the relationship between these tRNA genes change and codon usage bias,the relative synonymous codon usage（RSCU） in ten amphibian mitochondrial genomes was analyzed.The results showed that there was no difference in codon usage bias when tRNA gene was duplicated.This could be explained by that the long time of mutation accumulation,and the compactness of mtDNA prevent this change.Similarly,tRNA gene loss could not cause any obvious statistical change of the codon usage bias.For regular protein translation,there must be an effective functional replacement for the loss of tRNA genes.Two ways,that is,tRNA import and superwobble,cloud be the effective functional replacement for tRNA genes loss in amphibian mitochondrial genome.

关 键 词：两栖类 线粒体基因组 密码子使用偏好 tRNA基因重复 tRNA基因丢失 

分 类 号：Q953[生物学—动物学]