基于cpDNA非编码序列的北沙柳遗传多样性分析

Genetic Diversity of Salix psammophila Based on cpDNA Non-coding Sequence

为揭示北沙柳(Salix psammophila)的遗传多样性、遗传结构及分化特征,利用叶绿体非编码区序列(trnL-trnF和trnD-trnT)对分布于毛乌素沙地和库布齐沙漠的16个北沙柳居群(339个个体)进行了遗传研究,为北沙柳种子资源库遗传管理、遗传改良、遗传育种及品种选育提供理论依据。结果表明:(1)经trnL-trnF和trnD-trnT片段联合比对获得了1811 bp序列,共有12个核苷酸变异位点(8个简约信息位点,4个变异位点),得到16个单倍型。(2)单倍型多样性指数(Hd)为0.737,核苷酸多样性指数(π)为0.00107;且单倍型H3的分布在所有居群中位于单倍型网络图中心,其余单倍型随机分布于各个居群。(3)AMOVA分析表明,北沙柳cpDNA的变异主要来源于居群内(91.16%),居群间遗传分化程度中等(FST=0.08837),各居群间的基因交流非常频繁(Nm=2.58);遗传分化系数NST(0.085)显著大于GST(0.056,0.01<P<0.05),表明北沙柳居群具有明显的分子谱系地理结构。(4)中性检验及失配分析表明,北沙柳居群分布范围没有发生明显扩张的痕迹。

We used non-coding chloroplst DNA sequence(trnL-trnF and trnD-trnT)to study the genetic diversity of 16 populations of Salix psammophila distributed in Mu Us Sandy land and Kubuqi deserts,which aimed to explore genetic diversity,structure and differentiation characteristics of this species.This study provide theoretical basis for genetic management,improvement,breeding and variety selection of S.psammophila.The main results showed that:(1)the length of combine sequences was 1811 bp,a total of 12 nucleotide mutation sites were identified and 16 haplotypes were recovered,including 8 simple information sites and 4 mutation sites.(2)The haplotype diversity was 0.737.The nucleotide diversity was 0.00107.Only haplotype H3 located in the center of the haplotype network map distributed in all populations,while other haplotypes were randomly distributed among the populations.(3)AMOVA analysis suggest that 91.16%of the total variation existed within population while among population variation was medium(FST=0.08837).The exchanging of gene between the populations was very frequent(Nm=2.58).There is significant phylogeographic structure in population of S.psammophila.(NST=0.085,GST=0.056,0.01<P<0.05).(4)Neutral tests and mismatch analysis proved that the distribution of S.psammophila population did not expand significantly.