中文摘要：

对美洲大蠊等6种蜚蠊的线粒体CO I和Cyt b基因序列进行了分析,6种蜚蠊的CO I基因片段长度为659 bp,共存在221个核苷酸位点变异,变异率为33.54%;6种蜚蠊的Cyt b基因片段长度均为433 bp,共存在154个核苷酸位点变异,变异率为35.57%。本文以蜚蠊目近缘昆虫Neocapritermes taracua为外群,对CO I和Cyt b两个基因合并序列采用Neighbor-Joining法和Minimum Evolution法构建分子系统树。结果显示：两种方法均能区分美洲大蠊和另外5种蜚蠊,美洲大蠊和黑胸大蠊亲缘关系比较近。

英文摘要：

Mitochondrial CO I and Cyt b genes sequences of 6 Blattaria species were analyzed. The results showed that the CO I gene segments length was 659 bp for studied insects. There were 224 nucleotide variation sites with the variation rate of 33. 54%. The length of Cyt b gene segments were 433 bp,containing 154 nucleotide variation sites with a variation rate of 35. 57%. Neocapritermes taracua,as the outgroup,used Neighbor- Joining method and Minimum Evolution method to study the union sequences of CO I and Cyt b and to construct Blattaria＇ s molecular phylogenetic trees. It was suggested that the 2 methods analyses could be used in species identification of Periplaneta Americana and its closely related species.Accordant with the result derived from traditional classification system,our study revealed that the genetic relationship of Periplaneta americana and Periplaneta fuliginosa was nearer than with others.