扁蓿豆24个居群遗传多样性的SSR研究

Genetic Diversity of 24 Medicago ruthenica Populations Using SSR Markers

利用SSR技术研究分布于蒙古高原和大兴安岭地区24个扁蓿豆居群的遗传多样性,以明确扁蓿豆种群等位基因分布状况及在居群内和居群间的分异规律,揭示居群分布与环境的相关关系。结果显示:(1)利用紫花苜蓿的10个引物进行扩增,5个引物表现出多态性,共检测出15个等位基因变异,平均多态信息含量(PIC)为0.342 3。(2)24个扁蓿豆居群间基因分化系数(Fst)为0.17,表明扁蓿豆82.8%的变异来自居群内,基因流(Nm)为1.2。(3)聚类分析表明,24个扁蓿豆居群可聚成三大类,其中:大青山北部的扁蓿豆居群(hs)单独聚为一类,内蒙古高原东部、东南部和东北部的居群(kh、hb1、hb2、hb3、lq、lx、bl、zs、lh)聚为一类,蒙古高原东北部向大兴安岭的过渡区和大兴安岭地区的居群(dm、db、xs、eg、xb、eh、al、kj、aq1、dw、hb4、ys、aq2、xl)聚为一类。(4)遗传距离和环境条件关系的Mantel检验表明,地理位置(经度和纬度)的影响大于海拔,且大于单一的经度或者纬度(r=0.402 7,P<0.01);水平距离上,经度对遗传距离的影响大于纬度。

The genetic diversity of twenty four populations of Medicago ruthenica distributed in Mongolian Plateau and Daxing＇an mountain region was analyzed using simple sequence repeat （SSR） markers. This work aimed to know the genetic variation patterns within and among populations and the relationship be- tween population distribution and environments. （1）10 primers were used and five of them showed poly- morphism. The results indicated that 5 loci totally have 15 variation alleles,and the average polymorphic in- formation content（PIC） was 0. 342 3. （2）The variation among populations was lower which showed by gene differentiation coefficient （Fst= 0. 17） . There were 82.8~ of the variation in M. ruthenica within population,the gene flow （Nm） was 1.2. （3）The cluster analysis indicated the 24 populations could be di- vided into three distinct groups. The population in northern of Daqinshan （hs） was the single population group. The populations in east, southeast and northeast of Inner Mongolia（kh, hbl, hb2, hb3, lq, lx, bl, zs, lh） were assembled as the second group and the others from northeast of Mongolia plateau transition to the Daxinganling region （ din, db, xs, eg, xb, eh, al, kj, aql, dw, hb4, ys, aq2, x1） were assembled as the third group. （4）The Mantel＇s test of the relationship between genetic distance and the environment factors showed that the genetic distance among M. ruthenica was affected by altitude,latitude and longitude. The impacts of geographical location （latitude and longitude） was greater than altitude and the single latitude or longitude（r=0. 402 7,P%0.01）. Between latitude and longitude, the impact of longitude was larger.