基于微卫星标记的不同壳型湖北钉螺小尺度景观群体遗传结构研究

摘要

目的：分析湖北松滋地区湖北钉螺小尺度景观群体的遗传结构。方法选择 T 6-17、P101、D11、B14、T 4-33和C22等6对微卫星位点对松滋地区10个生境的湖北钉螺群体进行基因扫描，计算各群体的等位基因数（Na）、有效等位基因数（Ne）、期望杂合度（He）、观察杂合度（Ho）、多态信息含量（PIC）、群体间的遗传分化系数（FST ）和遗传距离，根据遗传距离进行聚类分析，并进行分子变异方差分析（AMOVA）。结果10个钉螺群体经鉴定螺壳分为光壳和肋壳（包括浅肋和深肋），10个群体共检测到141个等位基因，各位点20-34个不等，平均每个位点检测到23．5个；6个微卫星位点的平均有效等位基因数为1．575，各位点的有效等位基因数并不平衡，且数值差异较大，范围从0．445至3．060。群体的平均 H o范围为0．438-0．698，在光壳的团山村群体中最低，在深肋型的马木口村群体中最高；群体的平均H e范围为0．589-0．892，在浅肋型的德胜村群体中最低，在深肋型的马木口村群体中最高；成对群体间的Fst为-0．01564-0．25247，各群体的PIC为0．528-0．857，显示出高度多态性；AMOVA 分析结果显示，变异主要存在于个体间，占总变异的88．4％；聚类分析结果显示，肋壳的马木口村、横堤村、义兴村三个群体与光壳的马狮子咀村、民主村、土桥村三个群体先聚为一支后，与浅肋的德胜村、木天河村两个群体与光壳的团山村、夹马槽村聚的一支合聚。结论松滋地区不同景观环境下湖北钉螺呈现不同螺壳形态，尽管遗传多样性较为丰富，但遗传变异主要来自个体间，不同螺壳形态的湖北钉螺群体间并未体现出明显的遗传分化。%The genetic structure of small-scale landscape groups of Oncomelania hupensis in Songzi City ,Hubei Province was identify in this study .O .hupensis snails were collected from 10 habitats in Songzi City ,of which 6 polymorphic microsat-ellite DNA loci (T6-17 ,P101 ,D11 ,B14 ,T4-33 ,and C22) were carried out with GeneScan .The number of alleles (Na) ,het-erozygosity (H) ,fixation index (FST) of snails in each group ,genetic distance between groups ,and the polymorphic informa-tion content (PIC) were calculated .Cluster analysis was then carried out based on genetic distance ,and hierarchical AMOVA calculation was conducted .By certified the shells of snails ,10 groups were divided into light and ribbed shell (including shallow rib and deep rib) .There were 141 alleles in total detection on 10 populations and 20-34 alleles in each locus ,which were detec-ted for 23 .5 on average .The average number of alleles in 6 loci was 1 .575 and the number of alleles in each locus was uneven , showing large numerical differences ranged from 0 .445 to 3 .060 .The average observed heterozygosity (Ho) ranged from 0 .438 ue between paired populations was from -0 .015 64 to 0 .252 47 ,and the polymorphic information content in the population ranged from 0 .528 -0 .857 ,showing a high polymorphism .Hierarchical AMOVA calculations showed that inter-individual variation of the snails occupied 88 .4% of the total variations .Cluster analysis revealed that the three ribbed shell population in Munu Kou Village ,Hengti Village and Yixing Village first clustered to the three light shell population in Mashizizu Village , Mingzhu Village and Tuqiao Village ,then clustered to the light shell population in Tuanshan Village and Jiama Cao Village with the two shallow rib population in Desheng Village and Tianmu He Village .Under the different landscape environment of Songzi Area ,there were different shells presenting on the morphology of O .hupensis .Although there was a rich diversity on O .hupensis of Songzi City ,the genetic differences mostly present in individuals .Different groups didn’t show the significant genetic differentiation among the different shell morphology of O .hupensis .