The Genetic Structure Analysis Of Chinese Honeybee Population Based On MtDNA Sequence

Apis cerana cerana,which belongs to Hymenoptera,Apoidea,Apidae and Apis,is a kind of insect with significantly economic,social and ecological value.In this study,mitochondrial DNA(mtDNA)tRNAMet?tRNAGln,COI and Cytb genes were used as molecular markers to analyze the population genetic structure of Apis cerana cerana in 30 geographical populations from 18 provinces and cities in China.The theoretical results obtained in this study can help us to further understand the population genetic structure and genetic differentiation of Apis cerana cerana systematically,and can provide richer molecular theoretical basis for the conservation and rational use of Apis cerana cerana resources.The main results are as follows:1.A total of 150 samples from 30 locations were used in this study.The lengths of tRNAMet?tRNAGln gene sequences,COI gene sequences and Cytb gene sequences were respectively 232 bp,762 bp and 572 bp,and the combined gene was 1337 bp.In the combined gene sequences,the number of conserved sites,variable sites,parsimony informative sites,singleton sites were 1392,173,69,and 104,respectively.The number of haplotypes detected in the tRNAMet?tRNAGln gene sequences,the COI gene sequences,the Cytb gene sequences,and the combined gene sequences were 48,37,46,and 75,respectively.Based on the base composition analysis of each gene sequences,it was found that the content of A+T was significantly higher than the content of G+C,showing the bias of base composition.For the base composition of four gene sequences,the content of A+T in the tRNAMet?tRNAGln gene sequences,which reached 89.15%,was the highest.It was found that the overall haplotype diversity of 30 geographic populations was 0.981,and the overall nucleotide diversity was 0.0051 by analyzing the haplotype diversity and haplotype numbers of geographical populations of Apis cerana cerana.There was one haplotype of geographical populations in Dingxi of Gansu,Mingxian of Gansu,Minhe of Qinghai,Zunyi of Guizhou and Pingguo of Guangxi.And the haplotype diversity of Apis cerana cerana populations in Huanglong of Shaanxi,Baoji of Shaanxi,Qujing of Yunnan,and Shaoguan of Guangdong were high.2.By analyzing molecular variance(AMOVA)of Apis cerana cerana of 30 geographical populations,it was found that the variation of the populations of Apis cerana cerana in 30 geographical populations accounted for 62.48%of the total variation and the variation within the population accounted for 37.52%of the total variation.This result showed that the variation of Apis cerana cerana was mainly from population.The genetic differentiation Fst between geographic populations of Apis cerana cerana was from 0.014 to 0.965.and the genetic differentiation among most populations reached significant level,Most of the Apis cerana cerana populations had undergone different degrees of genetic differentiation.To calculate the genetic distance of Apis cerana cerana among different regions,the results showed that genetic distance between geographical populations ranged from 0.001 to 0.034.The genetic distance of Apis cerana cerana among three regions of Hainan was near,ranging from 0.003 to 0.005.while the genetic distance of Apis cerana cerana among Hainan province and other regions of the Chinese Mainland was far,ranging from 0.009 to 0.015.The isolation effect of Hainan Island was more obvious.The genetic distances of Apis cerana cerana between the other Chinese Mainland regions was small,ranging from 0.001 to 0.005.There is no obvious correlation between genetic distances and geographic distances of Apis cerana cerana.Geographic distance is not a determinant of the genetic structure of the Apis cerana cerana of different populations.3.Based on the tRNAMet?tRNAGln gene sequences and tRNAMel?tRNAGln+COI+Cytb gene sequences haplotypes,a phylogenetic tree and an Median-Joining network was constructed for 30 geographic populations of Apis cerana cerana respectively.The results show that the Apis cerana cerana in Hainan,Tibet and Sichuan Maerkang(Aba area)can be clustered together according to the corresponding geographic regions.However,the Apis cerana cerana in other regions could not be obtained similar results.It can be seen that the Apis cerana cerana in Hainan,Tibet and Sichuan Maerkang(Aba area)were more special than those in other regions.The clustering branch of Apis cerana cerana between Hainan and other regions was the most obvious,and the genetic distance of Apis cerana cerana between Hainan and other regions was the longest.Apis cerana cerana in Hainan may be a specific geographical population.Although the Apis cerana cerana in Tibet and in Sichuan Aba were clustered separately,their genetic distance from other geographical populations was also small.Therefore,it is believed that the Apis cerana cerana in Tibet and in Sichuan Aba may be special type under special geographical environment.Overall,the topological structure showed by the phylogenetic tree could not cluster the Apis cerana cerana populations in most regions according to the previous subspecies or ecotypes.Origin relations of the Apis cerana cerana populations in different regions were complicated.The research on the origin and evolution of the Apis cerana cerana needs to be further studied.4.This study used mtDNA tRNAMet?tRNAGln to analyze the genetic diversity and genetic structure of Apis cerana cerana,and constructed a phylogenetic tree to analyze the genetic differentiation of Apis cerana cerana.It was found that the mutation sites of tRNAMet?tRNAGln tRNAMet?tRNAGlngene were richer than other mitochondrial genes.Therefore,it can be used as an effective molecular marker to research the genetic diversity of the Apis cerana cerana.However,whether it can be used to resolve the genetic differentiation of the Apis cerana cerana remains to be further verified.