Genetic variations within and among four Leymus chinensis populations were evaluated using AFLP (amplified fragment length polymorphisms) markers. Eight primer combinations amplified 489 AFLP bands ranging from 85 to 550 bp. The genetic diversity and averaged percentage of polymophic bands (PPB) of the four populations showed similar trends, i.e. W＞H＞D＞J. The result of UPGMA (unweighted pair group method with arithmetic mean) based on the matrix of genetic distance indicated that individuals of the same populations were clustered together and that longitudinal rather than latitudinal gene flow was more frequent among the four natural populations. Two possible methods of gene flow, i.e. wind-mediated dispersal of pollen and seed transport via migrating birds are discussed.%羊草是我国北方草原群落重要的建群种和优势种.本研究应用AFLP(扩增片段长度多态性)的方法研究了4个羊草自然群落的遗传结构.应用8个引物组合,共得到489个AFLP带,从85到550 bp,结果表明,1)4个群落的遗传多样性和平均多态条带百分率有相似的趋势,即W(锡林浩特)＞H(海拉尔)＞D(大庆)＞J(长岭).2)用非加权配对算数平均法(UPGMA)聚类分析的结果表明,同一种群的个体亲缘关系近,而在不同种群之间经向基因流较纬向基因流更为频繁.探讨了形成这种现象的原因,即风向和候鸟在种群间基因流中的作用.
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