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橡实象虫(Curculio arakawai)是危害柞树果实(橡实)和嫩芽的主要害虫。基于探索害虫的系统发育和遗传进化机制的目的,以线粒体DNA(mitochondrial DNA,mtDNA)编码的细胞色素氧化酶Ⅱ(cytochrome oxidaseⅡ,COⅡ)基因作为分子标记,对橡实象虫及10个近缘种昆虫进行分子系统学研究。序列分析表明:橡实象虫及10个近缘种的mtDNA COⅡ基因序列全长687bp(不同橡实象虫样本获得的目的基因在GenBank的登录号包括GU945544、GU945545、GU945546),共编码228个氨基酸;mtDNA COⅡ基因表现出明显的A+T含量偏向性,密码子不同位点碱基的使用也存在明显的A+T含量偏向性,mtD-NA COⅡ基因的碱基颠换数总体上高于转换数,颠换主要发生在A←→T间,转换主要发生在T←→C间。遗传变异分析表明,橡实象虫及10个近缘种的核苷酸多态性位点百分率为39.7%,氨基酸突变率为30.3%。分别采用UPGMA法、NJ法和MP法构建橡实象虫及10个近缘种间的COⅡ基因系统进化树,各物种间的拓扑关系虽然稍有差异,但系统进化关系却完全一致,即物种间分别以所在的属聚在一起,形成Curculio、Ceutorhynchus和Peritelus3个属群,其中Curculio属和Ceutorhynchus属的系统进化关系较近,二者聚在一起形成一大支,而Peritelus属单独形成一支。
Curculio arakawai is a major pest that endangers oak (acorns) and shoots. Based on the purpose of exploring the phylogeny and genetic evolution mechanism of pests, the cytochrome oxidaseⅡ (COⅡ) gene encoded by mitochondrial DNA (mtDNA) Species of insects for molecular systematics. The sequence analysis showed that the mtDNA COⅡ gene sequence of Euglena equi and 10 closely related species was 687bp in length (GenBank accession numbers GU945544, GU945545, GU945546) Amino acids. The mtDNA COⅡ gene showed obvious bias in A + T content. The use of bases at different codons also showed significant A + T content bias. The base transversion number of mtD-NA COⅡ gene was generally high For the number of conversions, transversions occur mainly between A ← → T and conversions occur mainly between T ← → C. Genetic variation analysis showed that the percentage of nucleotide polymorphism loci was 39.7% and the amino acid mutation rate was 30.3%. UPGMA method, NJ method and MP method were used to construct the phylogenetic tree of COⅡ gene of elephant sand mites and 10 related species. Although the topological relationships among species were slightly different, phylogenetic relationships were completely consistent The genus Curculio, Ceutorhynchus and Peritelus are clustered together. Among them, Curculio genus and Ceutorhynchus genus have phylogenetic relationships, and the two are clustered together to form a major branch, while Peritelus is a separate genera .