Taxonomic Study Of China Firefly Based On DNA Barcoding

This study is about the mitochondrial cytochrome c oxidase subunit I of firefly and mainly describes the classification status,morphological characteristics and some problems of traditional classification method of Lampyridae insects.This research elaborated the application of DNA barcoding technology in firefly taxonomy in China,building a DNA barcoding database of China firefly.Also we measured and analysis the mitochondrial genome of the firefly,Asymmetricata circumdata,providing basic data for further phylogenic study of firefly.1.To build phylogenic tree based on COI geneWe amplificated the COI gene segment of 32 fireflies(7 unknown species)from 12 genus in 100 different geographical sites in China and obtained the COI sequence fragment of 711 bp.We analysis the base composition of the gene fragment,including conserved sites 164 bp,variable sites 547 p,parsimony information sites 483 bp and singleton sites 64 bp.The average content of the four bases is respectively: A=31.3%,T=38%,C=15.7%,G=14.9%.The results show that the COI gene of firefly is obviously A/T bases bias,similar with the high content of AT within insect mitochondrion.Through building phylogenetic tree,we can know that the classification result of Neighbor-Joining tree and the Maximum Likelihood tree according to the COI gene is completely same with the classification result based on morphological characteristics.The whole phylogenetic tree can be obviously divided into two branches.These results prove that it is useful for the classification research of China firefly to use COI gene.2.Analysis of genetic diversity about fireflies in different geographical populationsAmong the two subfamily of China firefly,the intraspecific genetic distance is0-0.082,the intraspecific genetic distance of Asymmetricata circumdata,Emeia pseudosauteri and Pyrocoelia pectoralis is larger than others,which shows these three species have higher genetic differentiation level.The interspecific genetic distance of firefly is 0.097-1.008,significantly greater than the intraspecific genetic distance.The result shows that there are DNA barcoding gap between the intraspecific genetic distance and the intraspecific genetic distance,which means we can use the genetic distance between different species to estimate whether they are the same species.3.To measure and analysis the complete mitochondrial genome of the firefly,Asymmetricata circumdataOur research measured and analysis the complete mitochondrial genome of firefly,A.circumdata.The complete mitochondrial genome sequence of A.circumdata(Gen Bank KX229747)has 15,967 bp and contains 13 protein coding genes,22 transfer RNA genes,2 ribosomal RNA genes(12Sr RNA,16 Sr RNA)and a non-coding AT-rich region of1388 bp.The circular genome of 15,967 bp has a base composition of A(42.44%),C(12.83%),G(8.79%)and T(36.16%).We sequenced the mitochondrial genome of fireflies to analyze phylogenetic relationships and deduce the evolution of their flashing signals.