入侵植物薇甘菊种群的遗传分化

POPULATION GENETIC DIFFERENTIATIONS IN THE INVASIVE PLANT MIKANIA MICRANTHA IN CHINA

利用简单重复序列区间(Intersimple sequence repeat,ISSR)分子标记技术分析了入侵植物薇甘菊(Mikania micrantha)8个种群的遗传多样性及遗传分化。12个引物共扩增出171个位点,其中多态位点有103个,多态位点百分率(P%)为60.23%,Shannon信息指数(I)为0.2818,Nei指数(h)为0.1849,薇甘菊在物种水平具有较高的遗传多样性。AMOVA显示薇甘菊具有较高的遗传分化,36.49%的变异发生在种群间,63.51%的变异发生于种群内,基因分化系数(GST)为0.3524。种群间的基因流较高,为0.9187。薇甘菊8个种群之间的遗传相似性很高,平均为0.9155;遗传距离很小,平均为0.0884。采用UPGMA法对8个种群进行聚类,可以将8个种群分为两大类群,即内伶仃岛为一个类群,而深圳与东莞内陆种群组成另一类群。薇甘菊现有遗传结构的形成与其生活史特性及入侵生态学特性有关。

Aims Genetic changes after introduction may contribute to the success of invasive plants. Our objective was to measure genetic diversity and genetic differentiation in the invasive Mikania micrantha in order to assess its invasive prospects. Methods Inter-simple sequence repeat （ISSR） markers were used to analyze genetic diversity and genetic differentiation in eight populations of M. micrantha. Important findings The 12 ISSR primers used in this study produced 171 loci, of which 103 were polymorphic. At the species level, the percentage of polymorphic loci （P） was 60.23 %, Shannon＇ s information index （I） 0.281 8 and Nei＇s gene diversity （h） 0. 184 9, indicating high genetic diversity in M. micrantha. Analysis of molecular variance （AMOVA） revealed that a high proportion （36.49%） of the total genetic variation was partitioned among populations, suggesting significant genetic differentiations among the eight populations of M. micrantha. Gene differentiation coefficient （GST） among populations was 0.352 4, and gene flow among populations was 0.918 7. Average genetic similarity of the eight populations was 0.915 5, while average genetic distance was 0. 088 4. Using unweighted pair group method arithmetic average （UPGMA）, the eight populations were clustered into two groups： the two populations on Neilingding Island were one group and the other six from China's Mainland were the other.