基于淫羊藿属(Epimedium L.)核型似近系数的聚类分析及其系统演化意义

为揭示淫羊藿属(Epimedium L.)植物染色体组遗传与进化,阐明该属植物系统亲缘关系和现代地理分布格局形成。该文对淫羊藿属植物51个分类群(43种、1亚种、6变种和1个栽培品种)和2种温哥华属(Vancouveria Morren et Decne.)植物的根尖进行了有丝分裂中期染色体核型分析,并运用核型似近系数聚类分析方法对这53个分类群植物的核型进行了聚类研究。结果表明:所有种类的染色体数均为12,二倍体(2n=2x=12),第1对同源染色体均为随体染色体,核型均为Stebbins的2A或1A型。可见,淫羊藿属植物染色体组在遗传进化中确实较为保守,种间核型非常相似。核型似近系数聚类分析为淫羊藿属植物系统进化研究提供了一些明显的线索。分析结果完全支持该属属下两个亚属(Subgen.Rhizophyllum和Subgen.Epimedium)的划分。亚属Epimedium的核型似近系数聚类结果显示,该类群物种间的系统亲缘关系与地理分布密切相关。核型似近系数分析结果还发现,来自东亚地区的淫羊藿属植物染色体组具有明显的变异,显示了更高的遗传多样性。基于上述研究结果,推断了淫羊藿属植物现代地理分布格局的形成过程。该研究结果可为淫羊藿属植物的资源利用、系统分类和遗传演化等领域的研究提供参考。

A cluster analysis of karyotype resemblance-near coefficients in genus Epimedium L. and its evolutionary and systematic implications

To reveal the genome genetics and evolution and clarify the systematic relationship and the formation of modern geographic distribution, a karyotype analysis of mitotic metaphase chromosomes in 51 Epimedium taxa(43 species, 1 subspecies, 6 varieties, and 1 cultivar)and two Vancouveria species was conducted in the present study. Especially, the 53 taxa studied were clustered by their karyotype resemblance-near coefficients because the interspecific karyotypes are very similar and the traditional karyotype analysis cannot provide significant evidence for the studies on genetics and evolution in Epimedium. The results were as follows: The 53 taxa studied all were diploid with 12 chromosomes(2n=2x=12), the genome of each taxon had one pair of satellites located on the pair I of homologous chromosomes, respectively, and the karyotype types of the 53 species studied all were type 1A or 2A of Stebbins. It can be concluded that the interspecific karyotypes were indeed very similar and the genomes evolvement were rather conservative in genus Epimedium. The cluster analysis of karyotype resemblance-near coefficients can provide some valuable clues for the studies on the systematics and taxonomy in genus Epimedium. Results of the cluster analysis by the karyotype resemblance-near coefficients strongly supported the previous taxonomic division of Subgen. Rhizophyllum and Subgen. Epimedium in genus Epimedium. The results also showed that the interspecific relationship was closely correlated to the geographical distribution in genus Epimedium and that the genomes of the taxa native to East Asia had obvious variation and more high genetic diversity. Finally, the formation of modern geographical distribution of genus Epimedium was inferred in the present study. Results of the present study have significant scientific values in the further studies on the resources utilization, taxonomy, and phylogenetics in genus Epimedium.