Cloning and comparative analysis of rDNA ITS2 and 5' terminal sequence of COⅠ gene of Frankliniella occidentalis
西花蓟马（Frankliniella occidentalis） rDNA ITS2和COⅠ基因5’末端序列的克隆与比较分析

Using PCR technique, both rDNA ITS2 and 5' terminal sequence of COⅠgenes of Frankliniella occidentalis were cloned and sequenced. Based on nucleotide sequences obtained in the present and from GenBank, the mutation type, nucleotide diversity, haplotype diversity and average intra-species genetic distance of rDNA ITS2 and COⅠ were analyzed and compared. Results show that COⅠ was a better candidate gene for detecting intra-specific polymorphisms, and to characterize genetic diversity;F. occidentalis may consist of two (or more) strains or cryptic (sub) species, and F. occidentalis population in China consisted of both greenhouse strain and lupin strain, with greenhouse strain as majority. Based on the knowledge thus far, we presumed that the first invaded area of F. occidentalis was Yunnan Province, and from there this exotic invasive insect dispersed to other parts of China, such as Beijing and Harbin. These results provide a basis for understanding the genetic diversity, strain composition and invasion mechanism of F. occidentalis in China.