基于线粒体COⅠ基因的齿小蠹属昆虫DNA条形码研究  

DNA barcoding based on the mitochondrial COⅠgene sequences for Ips species(Coleoptera:Scolytidae)

作　　者：常虹[1] 郝德君[1] 肖荣堂 刘勇 钱路[3] 安榆林[3] 杨晓军[3] 

机构地区：[1]南京林业大学森林资源与环境学院,南京2100372 [2]吴江出入境检验检疫局,江苏吴江2152003 [3]江苏出入境检验检疫局,南京210001

出　　处：《昆虫学报》2012年第9期1075-1081,共7页Acta Entomologica Sinica

基　　金：科技部国际科技合作项目(2009DFA31950);国家质检总局项目(2010IK256);国家科技支撑计划课题(2012BAK11B03)

摘　　要：齿小蠹属(鞘翅目:小蠹科)昆虫是植物检疫中经常截获的类群,为探讨线粒体细胞色素C氧化酶亚基Ⅰ(COⅠ)基因的特定区段作为DNA条形码快速准确鉴定齿小蠹种类的可行性,以齿小蠹属昆虫为研究对象,测定分析了线粒体COⅠ基因462bp碱基序列。序列分析结果显示:变异位点为259个,保守位点203个,简约信息位点181个,自裔位点78个。所有位点中,A,G,C和T碱基平均含量分别为30.7%,16.5%,17.0%和35.8%。A+T含量较高,为66.5%,明显高于G+C含量,表现明显的A+T碱基偏嗜,且A与T含量相当,符合昆虫线粒体基因碱基组成的基本特征。转换与颠换结果显示:该段序列未达到饱和,可以得到准确的进化分析。利用Kimura2-parameter模型分析遗传距离得到,同物种间的遗传距离介于0.002～0.007之间,不同种间的遗传距离介于0.056～0.431间,平均遗传距离为0.199,说明该段序列能够区分不同物种。基于COⅠ基因序列构建的邻接法系统发育树(NJ树)显示,同一物种聚为同一小支,且分支自展值均为100%;近缘种能聚集在一起,且置信度很高(≥97%)。结果表明应用基于COⅠ基因片段的DNA条形码进行齿小蠹属昆虫分类鉴定具有可行性。Species of the genus lps （Coleoptera： Scolytidae） are often intercepted and captured in quarantine at port. To explore the feasibility of identifying Ips species rapidly and accurately by DNA barcode of special sequence in mitochondrial cytochrome c coxidase subunit I （CO I ） , the 462 bp sequence of mitochondrial CO [ gene in Ips spp. was measured and analyzed. The sequence analysis results revealed that there are 259 mutation sites, 203 conserved sites, 181 parsimony-informative sites and 78 singletons in this gene. Among all sites, the average proportion of base A, G, C and T are 35.8% , 17.2% , 16.5% and 30.5% , respectively. A ＋ T base pair accounts for 66. 3% of the mitochondrial CO ] gene, which is significantly higher than that of G ＋ C base pair and shows an obvious preference to A ＋ T in the sequence. The numbers of A and T are equal, conforming to the basic feature of base composition in insect mitochondria. The result of transition and transversion showed that the sequence did not reach saturation and an evolution analysis can be achieved accurately. Model Kimura 2-parameter was used to analyze the genetic distance, and the results showed that the genetic distance among the same species varied from 0. 002 to 0.007, while that among different species ranged from 0.056 to 0.43l with the average value of 0. 199, confirming that the genetic distance can be used to discriminate different species. Neighbor-joining phylogenetic tree was built based on the CO I gene sequences, and the result indicated that the same species was gathered in the same branch, with the bootstrap value of 100% and the related species could also gather in the same branch, with a highconfidence （≥97%）. The results suggest that DNA barcoding based on mitochondrial CO I gene sequences is applicable in the classification and identification of Ips species

关 键 词：齿小蠹属 DNA条形码 线粒体COⅠ基因 遗传距离 系统发育树 

分 类 号：Q968[生物学—昆虫学]