Study Of Taxonomic And Molecular Systematics Of Phlebotomine Sandflies Based On Morphological Characters And Cytb Gene

ObjectiveTo explore the weight of different features under different kinds of Genus by two step clust analysis. To discuss the taxonomy position and genetic relationship of some species of Phlebotomus by sequencing and analysing Cytochromes b gene. To provide reference on molecular level for development and evolution of Phlebotomine sandflies.Methods(1) 14 species of Genus Phlebotomus and 27 species of Genus Sergentomyia sandflies from China as taxa and 52 morphological characters respectively as index were analysed by Two-step cluster analysis on SPSS13.0 software.(2) Some species of sandflies were caught in different places and identified using classic classifications method. After DNA extraction, PCR amplification and sequencing of Cyt b were carried out; The sequences of Cyt b were checked, revised, assembled, compared and analysed through molecular biology software. Genetic distance were calculated and molecular system tree were constructed.Results(1)The results by Two-step cluster analysis showed that they were perfectly consistent with traditional classification on Genus Phlebotomus. But in the Genus Sergentomyia, the taxonomic positions in some species were different from that in traditional classification. S. bailyi, S. campester, S. fanglianensis were assigned as a group, S. yunnanensis, S. lanzhouensis, S. tangi, S. turfanensis, S. suni were distributed as a group. This results suggested that they may occupy a new subgenus. Different features held the different weight in each group. It suggested that some characteristics should be paid more attention in classification.(2) The sequences of Cytb in P.lengi, P.yunshengensis, P.kiangsuensis, P.chinensis were all 432 bp. Among these sequences, the average percentage of A+T was 77.8%, whileC+G was 22.1%. It was showed with high A+T bias in Cytb. The average TS/TV ratio was 0.69.The relationship of 4 species were ((P.yunshengensis, P.lengi) and (P.kiangsuensis, Pchinensis)). The sequences of Cytb gene in 16 individuals of P.yunshengensis collectd from 3 regions showed different with each other, and the geographical differences were occured.ConclusionTwo-step cluster analysis results show that they were perfectly consistent with traditional classification on Genus Phlebotomus, but the numerical classification results is different from the results of traditional classification in Genus Sergentomyia. It reveals the uncertain classifications in some species. Different features show the different weight in each group, some characteristics should be paid more attention in classification. The difference between Cytb gene molecular tree and traditional classification of 4 species in Genus Phlebotomus suggests that Cytb gene should be used cautiously in solving relationship between Genus and Subgenus. Cytb gene is more suitable for analysis the same species in different geographical location.