Sequencing Of Mtdna Coi Gene For Identification Of Necrophagous Flies In Zhengzhou

Necrophagous flies colonize the dead body after organism is dead. the obvious discipline of the constitution and succession of necrophagous flies community appears at different postmortem interval. the discipline have been demonstrated by Recent studies, so we can estimate the post mortem interval (PMI) by this discipline in theory. Species within different family differ in their developmental times, so an accurate identification of every Species is the first step for the correct estimation of the PMI. Identification of specimens is traditionally performed using their morphological feathers. Now, this technique is very Self-contained.The morphological similarity of necrophagous flies especially their eggs larvae and pupae, poses a challenge for forensic entomologists. To solve the problems of identification of necrophagous flies' all of eggs and the first stage of larvae could not be identified only using their morphological feathers, Forensic entomology is always looking for a method more better than the morphologicald identification ways. as the progress of the theory and technology in molecular biology , a molecular method was established for species identification, The recently study indicated that species identification based on DNA examination is a better way . In this study, a region of mitochondrial DNA coding for cytochome oxidase subunit one (COI) was investigated for identification of the species of necrophagous flies from the central plains of China at different time from March to September every year.Methods 17 Samples (including eggs,larvae,pupae)were collected on the corpses of rats which were placed at three different locations(including zhengzhou urban district,east and west suburban district) in the zhengzhou district. The mtDNA of flies was extracted using the Improvement in grinding tissue during extracting DNA from small insects technique. Reactions were conducted on a PCR thermal cycler. PCR products were investigated by vertical non-denaturing polyacrylamide electrophoresis and purified using the Nucleic Acid Purification Kit. Sequences of both strands were obtained. The sequence alignment was carried out Using the multiple-alignment program CLUSTALx . A tree of phylogeny was constructed using the MEGA3.1 package.Result The analysis of each region of the gene for CO I encoding region of mtDNA of necrophagous flies collected from different locations in zhengzhou district on the corpses of rats showed less than 1% sequence divergence within species and more than 3% divergence between species. The tree of phylogeny showed that the 17 Samples were clustered four species.Conclusion The identification result through Sequencing the COI of mtDNA of 17 necrophagous flies, samples is as same as the the morphologicald identification result. moreover, the molecular method can resolve the problem of all of eggs and the first stage of larvae could not be identified. So it is a good method of identification of specimens, and there is practical value.