Stappen J V, Weltjens I, Munaut F, Volckaert G
Laboratory of Gene Technology, Katholieke Universiteit Leuven, Belgium.
C R Acad Sci III. 1999 Jun;322(6):481-90. doi: 10.1016/s0764-4469(99)80098-5.
The chloroplast trnL (UAA) intron and trnL (UAA)-trnF (GAA) intergenic spacer region have been sequenced from 37 samples, 36 of which representing 19 Stylosanthes species and one from the related genus Zornia. The DNA sequences were used to study phylogenetic relationships in the tropical forage legume genus Stylosanthes, by means of parsimony analysis using the heuristic search method of the computer program PAUP. The resulting cladograms divide Stylosanthes into four separate clades. Within the clades, species are poorly resolved owing to low sequence divergence. Small intra-specific chloroplast DNA variation is observed in S. humilis, S. scabra and the species complex S. guianensis. Variation between S. humilis populations is considered to be geographically structured. The overall results agree well with previously established inter-specific relationships and provide evidence for the genetic origin of the alloploid species S. hamata, S. scabra, S. ingrata, S. sympodialis, S. subsericea, S. capitata and S. fruticosa. This understanding of evolutionary relationships in Stylosanthes, in combination with biogeographical concepts provides a way of discerning isolated habitats in Central and South America, which may therefore contribute to strategies of plant collecting.
已对37个样本的叶绿体trnL（UAA）内含子和trnL（UAA）-trnF（GAA）基因间隔区进行了测序，其中36个样本代表19种柱花草属植物，另一个样本来自近缘属丁癸草属。利用计算机程序PAUP的启发式搜索方法，通过简约分析，将这些DNA序列用于研究热带豆科牧草柱花草属的系统发育关系。得到的分支图将柱花草属分为四个独立的分支。在这些分支内，由于序列差异较小，物种的分辨率较低。在矮柱花草、粗糙柱花草和圭亚那柱花草复合种中观察到种内叶绿体DNA的微小变异。矮柱花草种群之间的变异被认为具有地理结构。总体结果与先前确定的种间关系非常吻合，并为异源多倍体物种钩状柱花草、粗糙柱花草、无柄柱花草、合轴柱花草、绢毛柱花草、头状柱花草和灌木柱花草的遗传起源提供了证据。对柱花草属进化关系的这种理解，结合生物地理学概念，提供了一种识别中美洲和南美洲孤立栖息地的方法，因此可能有助于植物采集策略。
