Molecular Systematics of Araceae

天南星科植物包括食用植物（芋头）、观赏植物，以及世界上潮湿的热带森林中生态重要的成员，如黄花菜、红掌和怪物。在大约100个属之间的分类关系尚不清楚，部分原因是这些植物的形态特征以复杂的马赛克式方式发生。罗格斯大学（Rutgers University）的詹姆斯·弗兰奇（James French）博士正在研究从几乎所有已知属的代表性物种的叶片组织中分离出来的叶绿体DNA突变，以获得一个独立的数据集来建立这些物种之间的进化关系。叶绿体DNA是基因组数据的有用来源，因为它的结构和功能总体上是受限的；亲缘关系密切的植物只有少数突变，而更古老的分化群体则表现出更多的突变差异。通过测量不同类群之间叶绿体DNA突变差异的数量和种类，弗兰奇博士正在为这个家族构建一个系统发育树。这张分类关系图将有助于改进这些植物的分类，将相关属组织到相同的部落和亚科中。以系统发育为指导，研究人员可以研究复杂形态的进化和各种已知的家庭成员的繁殖系统。

The plant family Araceae (the aroids) includes food plants (the taros), ornamentals, and ecologically important members of the wet tropical forests of the world such as philodendron, anthurium, and monstera. Taxonomic relationships among the estimated 100 or so genera are poorly known, in part because morphological features occur in a complex mosaic-like fashion among these plants. To acquire an independent dataset for establishing evolutionary relationships among the aroids, Dr. James French of Rutgers University is studying mutations in chloroplast DNA isolated from leaf tissues of representative species of nearly all known genera of the family. Chloroplast DNA is a useful source of genomic data because its structure and function are constrained overall; closely related plants differ by only a few mutations while more anciently diverged groups show greater numbers of mutational differences. By measuring the amounts and kinds of mutational differences in chloroplast DNA among aroid genera, Dr. French is constructing a phylogenetic tree for the family. This diagram of taxonomic relationships will help improve the classification of these plants, organizing related genera into the same tribes and subfamilies. With a phylogeny as guide, researchers can study the evolution of the complex morphology of aroids and the various breeding systems known for members of the family.