Molecular Evolution Of The Meconematinae Based On COI And 12S RRNA Sequences

The Subfamily Meconematinae (Orthoptera: Tettigoniidae) which is a large group in family Tettigoniidae recorded 78 genera and about 550 species in the world. For a long time, there is little research about the phylogeny of the subfamily Meconematinae.This subject preliminary studied about the phylogeny of the subfamily Meconematinae based on the analyses of COI, 12S rRNA gene sequences.Summarizing these results, we can draw conclusions as follows:1. We got partial sequences of COI gene from 24 speices of 10 genera and 12S gene. from 18 species of 9 genera mainly using the method of PCR directly sequencing.2. It is found that COI gene sequences of studied Meconematinae species shows a strong A+T bias and same as 12S rRNA gene. The average content of A+T in COI gene sequences is 63%, and 72.9% in 12S rRNA gene. The length of COI gene is 610bp after multi-compaired, there are 385(63.1%) Conserved sites,225(36.9%) Variable sites, and 202(33.1%) Parsimony Informatic sites. The length of 12S rRNA gene is 611bp, there are 429(70.2%) Conserved sites, 178(29.8%) Variable sites, and 131(21.4%) Parsimony Informatic sites.3. The average transition and transversion ratio of COI gene sequence is 1.18 and 12S rRNA gene sequence is 1.42. Transition is higher than transversion. Sequence substitution saturation analysis indicates that the substitution is not saturated and so the sequence data sets can be used for phylogenetic analysis.4. MP, NJ and ML methods are separately used to reconstruct the phylogenetic relationships based on the data sets of COI gene, 12S rRNA gene and combined data sets. We found MP, NJ and ML phylogenetic trees. Based on the comprehensive tree topologies, we can conclude the results of phylogenetic and systematic of these species: (1) The phylogenetic and systematic relationship based the phylogenetic trees is partly agree with the morphology system. COI gene can identify the species correctly, and there are also some cryptic species in Meconematinae. (2) The result does not completely support the system of the genera of Meconematinae. Alloxiphidiopsis, Decma and subgenus Eoxizicus of Xizicus are reliable based on the molecular data. Other genera are not supported by the results.(3) The relationship of genus Xizicus and Paraxizicus are close and so do the Kuzicus, Teratura and Alloxiphidiopsis. (4) The genera of Tamdaora、Nipponomeconema and Teratura are ancestral groups and the genus Xizicus evolutional.(5)The monophyly of long wing species and short wing species was not supported.