Utility Of The Cytochrome Oxidase I (COI) For Conocephalinae Relatived Species Identification And Molecular Evolution (Orthoptera: Tettigoniidae )

In the research a short sequence of 612 bp of the mitochondrial gene COⅠwas used to investigate its utility to identify the relatived species of Conocephalinae. 124 mitochondrial COI gene from a total of 35 species in 10 genera were sequenced to obtain mtCOⅠDNA data. With the COⅠgene data, we analysized the phylogeny of 4 genera, and the experiment can provide more evidences and information for further molecular biology research of Tettigoniidae insects.Gampsocleis gratiosa was selected as outgroup, and its COⅠsequence was downloaded from GenBank. Using MEGA 5.03, the Base composition, Base substitution rates, Uncorrected p-distance and Variable base sites among species were analysed. Phylogenetic trees of 4 genus, Ruspolia, Conocephalus, Conanalus and Hexacentrus were reconstructed in PAUP 4.0 using NJ (neighbor-joining) method based on K2P model. The conclusions are as follows:1. All the mtCOⅠDNA sequences of Conocephalinae presents a high A/T bias: Among the sequences, average percentage of A+T is 58.2~63.6%.2. Base substitution analysis showed transition mostly occoured between T and C, and transversion mostly occoured between A and T. The most base substitutions occoured on the 3rd sites of codon.3. The topological structure of Ruspolia mtCOⅠDNA NJ tree conformed with the taxonomic view. 7 species divided into 2 clades: CladeⅠconsisted of R. interruptus, R. dubius, R. liangshanensis, R. jezoensis, R. yunnana, and R. dubius R. liangshanensis R. jezoensis had more close relationships; R. indicus and R. lineosa are the sister groups, composing cladeⅡ.4. The NJ tree of Conocephalus did not provide so much information about the phylogeny, but the monophyly of the species that sampled 2 or more individuals were supported by the phylogenetic tree. Hence, COⅠgene can be used in the molecular identification of Conocephalus species. Combining the p-distance and morphological characteristics, we identified C. percaudatus had 2 wing-forms: macropterous and brachypterous. To analyze the genetic relationship of Conocephalus species, more molecular markers are needed. 5. NJ tree of Conanlus did not show the phylogenetic relationships of 3 species. 3 species can form 3 branches separately, and the individuals sampled from the same place formed a secondary branch with high bootstrap value. So COⅠgene can be used to identify Conanalus species. With the data of genetic distances and interspecific different sites, we can concluded that C. axinus and C. robustus have more close relationship.6. The topological structure of Hexacentrus NJ tree supported the morphological conclusion, H. unicolor and H. japonicus constituted a branch, having close relationship.7. With the p-distance and morphological characteristic a new species of Anelytra was found.