基于nrDNA GapC基因内含子序列的资源冷杉遗传多样性研究

Genetic Diversity of Endangered Plant Abies ziyuanensis Based on nrDNA GapC Gene Intron Sequences

通过nrDNAGapC基因内含子序列的测序和分析,揭示资源冷杉遗传多样性水平和种群分化的强弱并推断其进化历史。资源冷杉3个种群的34个个体共获得70条GapC基因内含子序列,有8个核苷酸变异位点,鉴别出12种单倍型。银竹老山、大院和舜黄山种群分别有10种、6种和7种单倍型;有7个个体得到了2种以上的单倍型。资源冷杉物种水平的单倍型多样性（h）为0.817 0,种群的在0.683 3~0.883 1之间;物种水平的核苷酸多样性（π）为0.003 90,种群的在0.002 63~0.003 82之间。种群遗传分化研究结果（Gst=0.103,p〈0.05）说明种群间存在显著的遗传分化,分子方差分析（AMOVA）结果也证明虽然大多数的核苷酸多态性（88.64%,p〈0.001）来源于种群内个体间的变异,但是仍有显著性比例存在种群间（11.36%,p〈0.05）。Tajima’s D、Fu＆Li’s D、Fu＆Li’s Fs中性检验结果都表明资源冷杉在物种和种群水平上都不拒绝中性进化。资源冷杉单倍型的谱系没有出现地区特异性谱系分支,核苷酸不配对分析（mismatch analysis）结果表明没有发生近期的群体扩张,资源冷杉的Nst（0.131）与Gst（0.103）没有显著性差异（p〉0.05）,表明种群没有明显的地理结构。推测现存资源冷杉是相对较近的时间内片断化的产物。

In order to analyze the genetic variation and differentiation as well as the evolutionary history of Abies ziyuanensis,the nrDNA GapC gene intron sequences were used in this study.Eight polymorphic nucleotide sites and twelve haplotypes were detected from seventy alleles sequences of thirty-four samples from three A.ziyuanensis populations.Yinzhulaoshan（YZ）,Dayuan（DY） and Shunhuangshan（SH） populations had ten,six and seven haplotypes,respectively.Seven individuals had more than two kinds of haplotypes.The haplotype diversity（h） of A.ziyuanensis was 0.817 0,ranging from 0.683 3 to 0.883 1 for different populations.The nucleotide diversity（π） of species and population was 0.003 90,ranging from 0.002 63 to 0.003 82.Research result of genetic differentiation（Gst=0.103,p〈0.05） indicated that there was significant genetic differentiation among populations.AMOVA showed 88.64%（p〈0.001） genetic variation within population and 11.36%（p〈0.05） significantly genetic differentiation among populations.In Tajima’s D,Fu ＆ Li’s D and Fu ＆ Li’s Fs neutrality tests,the variation in nucleotides did not deviate from that expected with neutral evolution.There was no unique district branches in the gene genealogies of haplotypes.The result of mismatch distribution analysis showed no recent rapid expansion and no significant difference（p〉0.05） between Nst（0.131） and Gst（0.103）,which indicated no obvious geographic structure exists in A.ziyuanensis.We inferred that the extant A.ziyuanensis populations might be resulted from the habitat fragmentation in a relatively recent period.