近缘物种的遗传多样性及其亲缘关系的取样策略研究

取样策略的问题目前大多停留于对单一物种的种质资源研究.然而,对野生近缘植物取样策略的研究,不仅有利于准确快捷地阐明物种间的系统发育关系,而且对于了解遗传多样性分布状况,制定野外考察、材料收集取样及保护策略均有重要的理论指导意义.以巴山松及其近缘种为例,利用cpSSR(叶绿体微卫星)和AFLP2种分子标记对其取样策略和统计方法进行分析,揭示居群取样个体数和基因位点数与遗传多样性的关系以及基因(引物)和系统树构建方法对亲缘关系确定的影响.研究表明:(1)居群取样个体数和基因位点数差异对遗传多样性影响并不显著,但当居群取样个体数为30个左右,单引物基因位点数为60个以上,总位点数为480个以上时,所得遗传多样性及亲缘关系较为准确可靠.(2)较多数目的基因(引物)对于得到较为准确可靠的亲缘关系分析是十分必要的.(3)系统树构建方法对近缘种亲缘关系的确定有一定的影响.

Sampling Strategy for Genetic Diversity and Genetic Relationship of Relative Species

At present,sampling strategy is mostly involved in germplasm resources of single species.However,it is also great importance to expound phylogenetic relationship,genetic diversity,and conservation strategies of wild kindred plants.In this paper,Pinus henryi and its relative species were involved in sampling strategies and statistical methods analysis using chloroplast microsatellites(cpSSR) and AFLP markers.The results showed some differences with present views.Firstly,the effect of sample sizes/loci on genetic diversity was not significant.When sample size increased to 30 and gene loci to 60 per primer pairs with 480 in total,genetic diversity and phylogenetic relationships were more exact and credible.Secondly,more primer pairs(genes) were necessary to obtain credible genetic diversity and phylogenetic relationships.Thirdly,phylogenetic relationships among relative species were notably affected by methods of phylogenetic trees construction.