摘要
[目的]本研究旨在对蝎蝽次目11科线粒体基因组中13个蛋白质编码基因(PCG)的密码子使用情况、A+T含量、氨基酸序列和核苷酸序列信息位点以及核苷酸进化速率进行比较研究,同时基于13个PCG序列构建蝎蝽次目系统发育树。[方法]通过GenBank获得蝎蝽次目所有14个代表种的PCG序列,统计蝎蝽次目起始密码子和终止密码子的使用频率。在BioEdit 7.1中计算核苷酸串联序列第一位、第二位、第三位和一二三位密码子A+T含量。在MEGA 6.0中计算核苷酸串联序列和氨基酸串联序列的保守位点、信息简约位点和自裔位点。用软件DnaSP 6.0计算蛋白质编码基因每个位点的非同义替代率(Ka)和同义替代率(Ks),由此分析每个基因的核苷酸进化速率Ka/Ks。在RAxML 8.2.8和MrBayes 3.2.5中分别基于最大似然法和贝叶斯法构建系统发育树。[结果]蝎蝽次目昆虫起始密码子使用中,ATN的使用频率明显高于GTG和TTG。蝎蝽次目使用的4种终止密码子中,TAA和T的使用频率最高。蝎蝽次目每一位密码子的碱基组成含量表明第三位密码子的AT含量最高,远远高于第一位与第二位密码子。在氨基酸和核苷酸序列中,COI的保守位点数最多,ATP8和ND4L的保守位点数最少;ND5的简约信息位点数最多,其次为ND2和ND4。核苷酸进化速率的分析中,ATP8基因的进化速率最快,COI基因进化速率最慢。ML和BI的系统发育结果基本一致,分支关系如下:(划蝽总科+((蟾蝽总科+蝎蝽总科)+(潜蝽总科+(仰泳蝽总科+固蝽总科))))。[结论]本研究补充了蛋白质编码基因在蝎蝽次目比较线粒体基因组学研究中的不足,揭示了蛋白质编码基因在比较线粒体基因组学研究中的重要性。
[Objective]This study was aimed to investigate the codon usage,A+T content,amino acid sequence and nucleotide sequence information sites,and evolutionary rates of 13 PCG.A phylogenietic tree of the Nepomorpha based on 13 PCG gene sequences was constructed.[Methods]The PCG sequences of all 14 representative species of Nepomorpha were obtained from GenBank.The frequency of the usage of the start and stop codon were counted.The A+T content of the first,second,third codon of PCG and all sites of nucleotide tandem sequences was calculated in BioEdit 7.1.The conserved sites,parsimonious informative sites and singleton sites of amino acid and nucleotide sequence were computed in MEGA 6.0.The non-synonymous substitutions rate(Ka)and synonymous substitution rate(Ks)of each site of the protein-coding gene were conducted with DnaSP 6.0 to analyze the evolutionary rate of Ka/Ks for each PCG.We constructed phylogenetic trees in RAxML 8.2.8 and MrBayes 3.2.5 based on maximum likelihood(ML)and bayesian inference(BI),respectively.[Results]The use frequency of ATN was significantly higher than that of GTG and TTG.Among the four stop codons used in Nepomorpha,TAA and T were used most frequently.The base composition content of each codon of the Nepomorpha indicates that the third codon had the highest AT content,which was much higher than the first and second codons.Among the amino acid and nucleotide sequences,the number of conserved sites of COI was the highest,while ATP8 and ND4L had the lowest number;the greatest number of parsimony informative sites was observed in ND5,followed by ND2 and ND4.In the analysis of nucleotide evolutionary rate,ATP8 showed the fastest rate and COI was the slowest one.The phylogenetic trees of ML and BI were consistent,and the branching relationship was as follows:(Corixoidea+((Ochteroidea+Nepoidea)+(Naucoroidea+(Notonectoidea+Pleoidea)))).[Conclusion]This study supplemented the deficiencies of PCG study in Nepomorpha and revealed the importance of PCG in comparative mitochondrial genomic study.
作者
张丹丽
李敏
张苗苗
田菁
李悦锐
张虎芳
Zhang Danli;Li Min;Zhang Miaomiao;Tian Jing;Li Yuerui;Zhang Hufang(Department of Biology,Taiyuan Normal University,Jinzhong 030619,China;Department of Biology,Xinzhou Normal University,Xinzhou 034000,China)
出处
《山西农业大学学报（自然科学版）》
CAS
北大核心
2020年第4期66-72,共7页
Journal of Shanxi Agricultural University(Natural Science Edition)
基金
山西省高等学校科技创新项目(2019L0810)
太原师范学院第四批青年学术骨干。
