福周艾蕈甲的线粒体基因组及系统发育分析

Mitochondrial genome and phylogenetic analysis of Episcapha fortunii

通过测序分析了福周艾蕈甲的线粒体基因组结构,并基于线粒体基因组数据,分别利用最大似然法和贝叶斯法重建了扁甲总科的系统发育树,内群包含扁甲总科的50种昆虫,外群为2种象甲总科昆虫。结果表明:福周艾蕈甲的线粒体基因组包含37个基因[13个蛋白质编码基因、2个核糖体RNA(rRNA)基因和22个转运RNA(tRNA)基因]和1个非编码控制区;整个线粒体基因组全长为15716 bp(GenBank序列号:OP354255)。13个蛋白质编码基因中除cox1和nad1的起始密码子为TTG外,其余以ATT、ATA或ATG为起始密码子;4个蛋白质编码基因cox1、cox3、nad5和nad4的终止密码子为T或TA,其余9个蛋白质编码基因的终止密码子为TAA或TAG。除trnS1因缺少二氢尿嘧啶(DHU)臂而无法构成稳定的三叶草结构外,其余tRNA基因均能形成典型的三叶草结构;trnS1的反密码子不是常见的GCU,而是UCU。rrnL基因的全长为1281 bp,A+T含量为81.73%;rrnS基因的全长为761 bp,A+T含量为79.50%。两种系统发育分析方法构建的系统发育树基本一致:大蕈甲科为非单系群,其与原扁甲科有较近的亲缘关系;福周艾蕈甲与光亮艾蕈甲构成姐妹群。

The mitochondrial genome of Episcapha fortunii Crotch,1873 was sequenced and analyzed for the construction of phyloge⁃netic trees with 50 Cucujoidea species as ingroups and 2 Curculionoidea species as outgroups by maximum likelihood and Bayesian inference methods.The mitochondrial genome of E.fortunii is 15716 bp in length(GenBank accession No.OP354255)and contains 37 genes,which is made up by 13 protein⁃coding genes,2 ribosomal RNA(rRNA)genes,22 transfer RNA(tRNA)genes and a non⁃coding control region.The start codon of most protein⁃coding genes is ATT,ATA or ATG,except for the cox1 and nad1 gene u⁃sing TTG as the start codon.Although cox1,cox3,nad5 and nad4 employ the incomplete stop codon T or TA,the remaining 9 pro⁃tein⁃coding genes terminate with TAA or TAG.Most tRNAs can be folded into typical cloverleaf structure except for trnS1⁃encoded tRNA which has no dihydorouridine(DHU)arm.The anticodon of trnS1⁃encoded tRNA is not a common GCU,but UCU.The length and A+T content of rrnL gene are 1281 bp and 81.73%,respectively,and those of rrnS gene are 761 bp and 79.50%.Both inference methods produced similar phylogenetic trees,in which Erotylidae is a non⁃monophyletic group with close relationship to Protocucujidae,and E.fortunii and E.opaca are clustered as sister group.