Genetic diversity of Conocephalus maculatus of different geographic populations based on mitochondrial DNA control region analysis
基于线粒体DNA控制区的斑翅草螽不同地理种群遗传分化研究

Polymorphism of sequence variations in mitochondrial control region was assessed to explore the level of genetic variability and differentiation among nine populations of Conocephalus maculatus (Orthoptera: Tettigoniidea) from China and Filipine. PCR was used to amplify the control region fragment in 66 individuals of C. maculatus collected from Chongqing (CQ), Filipine (FLB), Guangxi (GX), Hebei (HB), Hainan (HN), Jiangxi (JX), Sichuan (SC), Xizang (XZ) and Yunnan (YN). A mitochondrial DNA (mtDNA) fragment of 1259 aligned bp was sequenced in these 66 C. maculatus individuals. The fragment sequenced for each of the 66 individuals that include a partial sequence of rrnS, control region, trnI, trnQ, and a partial sequence for trnM. The size of control region was 676 bp, with nucleotide frequencies of T (37.8%), C (11.7%), A (41.3%) and G (9.1%). A Total of 46 haplotypes from 66 mtDNA control region sequences were identified, with 98 variable sites (14.5% of total analyzed sites). Only four of these haplotypes were shared by individuals from more than one population, six haplotypes were shared by more than one individual within population. The analysis of molecular variance (AMOVA) showed that the percentage of variation within populations (62.94%) was greater than that among populations (37.06%). In the hierarchical AMOVE, both the 'among populations' and 'within populations' variance components were considerable high, the latter was more contribution to total variances than the former. Levels of genetic variation within C. maculatus populations were higher than among them. FST analyses reveals that no significant (P>0.05) genetic differences between SC and CQ, and between any two populations of GX, FLB, HN and YN. There are significant (P<0.05) genetic differences between remaining any two populations. We may be a preliminary clustered them into four groups, SC+CQ,GX+FLB+HN+YN,XZ and HB. Phylogenetic analyses between the 46 haplotypes based on Neighbor-Joining cluster into three phylogenetically well supported clades. Clade A is formed with 28 haplotypes from all populations other than SC and CQ; Clade B is formed with 12 haplotypes from all populations other than FLB and JX; Clade C is formed with 6 haplotypes from XZ population. These results may suggest that no significant genetic differences among populations, even for those FST analyses significant (P<0.05) populations.