Dissertation Research: Phylogenetic Systematics of Cacao and its Relatives (Byttnerieae: Sterculiaceae)

9700876鲍姆研究生芭芭拉·惠特洛克在哈佛大学大卫·鲍姆博士的指导下，为了分类学和系统发育的目的，正在研究新热带植物属Theobroma，它是可可或巧克力的来源，以及它属于梧桐科Byttnerieae部落的近亲。中美洲和南美洲的新收藏品将增加植物标本馆的材料，并有助于改善对该群体形态和地理变异的了解。新的分子生物学证据正在从一个叶绿体基因和一个核基因vicilinA的DNA序列中收集，该基因被怀疑参与可可的风味生物化学。DNA数据将被用来推断西奥布罗马及其近亲约22种的系统发育树。反过来，这种系谱观点将指导进一步研究该属和相关属的花序起源，沿着植物的主干和主茎形成花(和授粉后的果实)，如巧克力的商业来源Theobroma Cacao。尽管栽培可可具有重要的商业价值，但对该属几个种的分类和系统发育研究还不是很好，而将新的分子方法应用于标本标本库和新收集的标本将有助于改进分类并建立该组的系统发育图。这些知识将有助于指导对影响热带植物花茎进化的遗传和生态因素的研究。

9700876 Baum Graduate student Barbara Whitlock, under the direction of Dr. David Baum of Harvard University, is studying the neotropical plant genus Theobroma, the source of cocoa or chocolate, and its relatives of the tribe Byttnerieae of the Sterculiaceae family, for taxonomic and phylogenetic purposes. New collections in Central and South America will augment herbarium materials, and help improve understanding of morphological and geographic variation in the group. New molecular biology evidence is being gathered, from DNA sequencing of a chloroplast gene and of a nuclear gene, vicilinA, suspected to be involved in the flavor biochemistry of cocoa. The DNA data will be used to infer a phylogenetic tree for the c. 22 species of Theobroma and its close relatives. In turn, that genealogical perspective will guide further study of the origins of cauliflory in this and related genera, the formation of flowers (and fruits after pollination) along the trunk and main stems of the plant, as in Theobroma cacao, the commercial source of chocolate. Despite the commercial importance of cultivated cocoa, the taxonomy and phylogeny of the several species of Theobroma are not well studied, and new molecular methods applied to herbarium and freshly collected specimens will help improve classification and develop a phylogeny for the group. That knowledge will then help guide studies of the genetic and ecological factors affecting the evolution of cauliflory in tropical plants.