Studies Of Some Species Of Dragonflies Coi Gene And 28srdna Gene Sequence And Molecular Systems

Odonata are attached Insecta Pterygota. Dragonfly is relatively small ancient winged insects. Existing 3 sub-orders types, including Anisoptera, Zygoptera and Anisozygoptera, (only two belong to two). Anisoptera are known as dragonflies, Zygoptera are known as damselflies. Worldwide, an estimated of 10,000 or so, there are 5600 kinds of dragonflies known, China has reported 663 kinds.Odonata are not only nature enemy inscts,but also medical and edible resource insects.The are reccgnized as being good indicators of the condition of aquatic and terrestrial ecosystems.So, there are great reseach value.The section-level classification of dragonfly has been a controversial issue, but also been a hotspot of phylogenetic reseach of Odonata. Odonata have been studied from such fields as Morphology, Taxonomy, Ecology, Behavioral Biology, Cell and Molecule Biology, Biogeography and so on. Currently, however, studies on molecular systematics of the classification of Acridoidea are still limited.In this paper, partial species of Odonata (21 species,15 genera,6 families) are studied from molecular systematics. The partial COI and 28SrDNA gene sequences of 21 species, and one outgroup species, Haplotropis neimongolensis as outgroup. The base frequences, base substitutions and genetic distances of DNA sequences have been analyzed by using Clustal X1.81,MEGA4.1,PAUP4.0 and MrBayesV3.1 softwares. Phylogentic signal have been tested via base substitution saturation analysis, g1 and PTP tests. Results show that there are strong phylogenetic signal in the data tests. Based on the analyses of CO I and 28S rDNA gene sequences, we reconstruct the phylogenetic relationships of these species from family level by using, Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian Inference (BI) methods.Summarizing these results, we can draw conclusions as follows:1. The mitochondrial COI gene sequences (662bp, not include outgroup) show a stong A/T bias.The average content of A+T is 63.2%, and the average content of G+C is 36.8%(20 specis of Odonata A=29.2%;T=34%;C=18.3%;G=18.5%).28SrDNA (571 positions) is well conserved with 453 invariable sits,108variable sites. There are great differences of two genes'composition, which may because theire evolution speed is different.2. MP, ML. and BI method are separately used to reconstruct the phylogenetic relationships based on the data sets of COI gene,28SrDNA gene and combined data sets. The result from comparing these trees indicates that topology of all the phylogenetic trees have little difference. The trees of combined data are very consistent and could clearly conclude the phylogenetic relationship. Therefor, the partial sequences of COI and 28SrDNA gene in the study can effectively reseach the phylogenetic relationship of Odonata, particularly result from the combined data are reseach more accurate.3. The result of phylogenetic trees show:(1) The family Libellulidae is a monophyletic group; The relationship of Sympetrum and Pantala are near; Libellula and Orthetrum are near; Lestidae and Coenagriidae are near. (2) Mnais maclachlani Fraser is more near Anisoptera than Zygoptera, which Contradicti with the morphological classification, so we need study more deeply on it. (3) Lestidae is more evolutionary in the 6 family and Libellulidae is more original. Orthetrum is more evolutionary in the Libellulidae and Crocothemis is more original.4.The results of the study which based on The partial COI and 28SrDNA gene sequences are consistent with the results of Morphology study. The relationship of the 6 family is:(((Lestidae, Coenagriidae), Agriidae), ((Aeschnidae, Gomphidae), Libellulidae))); The relationship of species of Libellulidae is:(Crocothemis,((Pantala,Sympetrum), (Libellula, Orthetrum))).