象甲科线粒体基因组特征及系统发育分析

Mitochondrial genome characteristics and phylogenetic analysis of the Curculionidae

昆虫线粒体基因组广泛应用于系统发育关系的重新建立、分子进化、谱系地理学及物种诊断等领域。为揭示象甲科昆虫线粒体全基因组序列的主要结构特征,探究其系统发育相关信息,为进化遗传学研究和分子标记选取等提供参考依据,本研究利用比较基因组学和生物信息学方法,对NCBI上已公布的35种象甲科物种线粒体全基因组序列进行了分析。结果显示:(1)象甲科tRNA基因存在排序及数目异常情况,不同物种中蛋白质编码基因和2种rRNAs排列相同,线粒体全基因组具有明显AT偏向;(2)COX1、ATP6、ND5、ND4、ND4L和ND1基因除标准三联密码子外,还存在特殊的起始密码子AAT、TTG和GTG;(3)13种蛋白质编码基因的进化速率顺序为COX3>ATP8>ND2>ND5>ND1>ND4>ND6>ND4L>ND3>ATP6>Cytb>COX1>COX2;(4)13个蛋白编码基因和rRNAs基因中,ND5、rrnL、ND4和ND2基因变异位点数较高,可作为备选的分子标记;(5)各亚科的系统发育关系可能为(((小蠹亚科Scolytinae+长小蠹亚科Platypodinae)+(隐喙象亚科Cryptorhynchinae+魔喙象亚科Molytinae+象虫亚科Curculioninae)+((孢喙象亚科Cyclominae+粗喙象亚科Entiminae)+(隐颏象亚科Dryophthorinae+长小蠹亚科))),为象甲科的系统发育分析有提供参考。

Mitochondrial genomes of insects are widely used in the reconstruction of phylogenetic relationships,molecular evolution,phylogeography and species diagnosis.To reveal curculionidae insects main structure characteristics of mitochondrial genome sequence and explore their phylogenetic information,which provided a reference for evolutionary genetics research and selection of molecular markers.Structural characteristics and phylogenetic relationships of 35 species in curculionidae were analyzed by using comparative genomics and bioinformatics.The results showed that:(1)tRNA gene of the 35 species exhibited genecombination and number abnormality,while coding genes and the two rRNA genes exhibited similar in different species.The all mitochondrial genomes showed obvious AT bias;(2)COX1,ATP6,ND5,ND4,ND4L and ND1 genes owned standard triplet codons and special initial codons,AAT,TTG and GTG;(3)Evolutionary rates of the selected 13 PCGs as follow:COX3>ATP8>ND2>ND5>ND1>ND4>ND6>ND4>ND3>ATP6>Cytb>COX1>COX2;(4)Among the 13 protein-coding genes and rRNAs,ND5,rrnL,ND4 and ND2 genes existed more mutation sites,which could be used as putative molecular markers;(5)The phylogenetic relationship of subfamilies might be(((Scolytinae+Platypodinae)+(Cryptorhynchinae+Molytinae+Curculioninae)+((Cyclominae+Entiminae)+(Dryophthorinae+Platypodinae))).The results could be devote to phylogenetic analysis of Curculionidae.