基于COⅠ基因的我国悬铃木方翅网蝽(半翅目:网蝽科)种群遗传多样性和遗传结构分析

Analysis of Genetic Diversity and Genetic Structure in Geographic Populations of Corythucha ciliata(Hemiptera:Tingidae)from China Based on Mitochondrial DNA COⅠGene Sequences

【目的】研究悬铃木方翅网蝽在我国不同地理种群间的遗传多样性和遗传结构,探讨其种群在我国的入侵趋势。【方法】共测定12个悬铃木方翅网蝽地理种群中240个个体COⅠ基因的部分核苷酸序列,利用DnaSP V6.12.03等软件对方翅网蝽不同地理种群间的遗传分化程度、基因流水平、分子变异情况、种群历史动态等进行分析。【结果】悬铃木方翅网蝽12个地理种群的COⅠ核苷酸序列含有13个变异位点和9个单倍型,其中有5个共享单倍型,Hap1为祖先单倍型。方翅网蝽总种群单倍型多样性指数Hd为0.584,地理种群间Hd值在0~0.758之间。种群总固定系数FST值为0.48,各地理种群间FST值在-0.05~0.89之间,种群间基因分化程度差异较大;种群总基因流Nm值为0.55,且各地理种群间Nm值在-85.25~47.58之间,种群间基因交流程度不同。悬铃木方翅网蝽种群内个体间变异占总变异的52.19%,同时华中组群经历了方翅网蝽种群扩张事件。【结论】12个悬铃木方翅网蝽地理种群在不同组群间和地理种群间具有显著分化的遗传结构。悬铃木方翅网蝽的遗传分化主要来自种群内个体间变异,各地理种群间遗传距离与地理距离无明显的相关性,地理距离未明显阻碍地理种群间的基因交流。同时,推测在中国主要分布区内悬铃木方翅网蝽以上海为中心向全国进行扩散。

【Objective】Corythucha ciliata(Hemiptera:Tingidae),an important invasive pest in China,mainly damages on Platanus plants.It has broken out in multiple regions of China.This research tries to explore the genetic differentiation among the geographic population of C.ciliata,and probe its spread path.【Method】The sectional nucleotide sequences of COⅠgene of 240 individuals from 12 geographic populations were determined.Based on their nucleotide sequences,the genetic differentiation,gene flow level,molecular variance,and population demographic history were analyzed by using DnaSP V6.12.03 and other analysis software.【Result】There were 13 mutation sites and 9 haplotypes in the COⅠgene among 12 geographic populations.Among them,5 haplotypes were shared by all the geographic populations,and the haplotype H1 was an ancestor haplotype.Haplotype diversity index(Hd)of the total population was 0.584,and the Hd value among geographic populations ranged from 0 to 0.758.The fixed coefficient(FST)of the total population was 0.48,and the value between geographic populations ranged from-0.05 to 0.89,suggesting that the degree of differentiation between different populations of C.ciliata was obviously different.Gene flow value(Nm)was 0.55 within the total population and ranged from-85.25 to 47.58 between geographic populations,indicating that the degree of gene exchange was distinct difference among populations.The individual variation within the populations accounted for 52.19%of the total variation,while populations of C.ciliata from the Central China experienced a population expansion event.【Conclusion】There are significant differentiation of genetic structures among different groups and different geographical populations of C.ciliata.The genetic differentiation of geographic populations primarily derives from variation of intraspecies.The genetic distance of the geographical populations is no significant association with geographical distance,and the geographical distance has no obvious effect on the gene flow of populations.Furthermore,we speculate that the insect spread from Shanghai as the center to other regions in China.