Abstract: Objective To analyze the gene characteristics of ribosomal internal transcribed spacer 2 sequence(rDNA- ITS2) in the 9 species of common mosquitoes for the basis in molecular identification of the mosquito species. Methods Nine species of mosquitoes, including Culex pipiens pallens, Culex tritaeniorhynchus, Culex bitaeniorhynchus, Aedes albopictus, Aedes vexans, Anopheles sinensis, Armigeres obturbans,Mansonia uniformis, Coquillettidia ochracea, were collected from Jining area in Shandong Province, and morphologically identified. Single mosquito genomic DNA was extracted from each species and rDNA-ITS2 was specifically amplified by PCR and sequenced. Then the gene sequences were subjected to homology align- ment in GenBank, compared and analyzed by Bioedit 7. 0 and DNAMAN. The gene traits were analyzed by DNASTAR, ClustalX 1. 81 and Mega6, and the phylogenetic tree was constructed. Results The amplified rDNA-ITS2 fragments for the nine species of mosquitoes varied from 343 bp to 577 bp, with 59 conserved sites, 449 variable sites, 235 parsimony informative sites and 191 singleton sites in the sequences. The nucleotide sequence homology among the different mosquito species was 28. 21% ~ 53. 76% , and the molecular identification of the species based on rDNA-ITS2 was consistent with the tradi- tional morphological findings. The results indicated that Culex pipiens pallens, Culex tritaeniorhynchus and Culex bitaeniorhynchus were clustered to Culex genera, and Aedes albopictus and Aedes vexans to Aedes genera, The different species was independent at its own taxonomy branch. Conclusion rDNA-ITS2 can serve as an useful classification for and molecular marker to iden- tify the species of different mosquitoes by genus.

Key words: