REU: Molecular Evolution and Adaptive Radiation in the Bromeliad Genus Brocchinia

Drs。威斯康星大学的Givnish和Sytsma正在研究凤梨科的凤梨属物种的进化史。这组植物具有科学意义，因为它们被认为是该科的原始成员，可能是向高级附生形式的过渡，因为它们原产于南美洲最古老的地区——圭亚那盾，还因为它们进化出了一系列引人注目的捕获矿物质营养的手段，包括食肉性，共生固氮，并以蚂蚁为食。调查人员将在委内瑞拉、巴西和哥伦比亚收集大约21种该属的标本。他们将通过分析叶绿体DNA来评估物种之间的基因组关系。将这些结果与花和营养性状的研究进行比较，将有助于评估传统解剖特征在分类学分类中的可靠性。这项研究的目的是了解这些物种是如何进化的，它们是如何适应极端土壤贫瘠的条件的，以及它们是如何在地质时期分散到南美洲北部地区的。

Drs. Givnish and Sytsma of the University of Wisconsin are studying the evolutionary history of species of the genus Brocchinia of the pineapple family, Bromeliaceae. This group of plants is of scientific interest because they are considered primitive members of the family and may be transitional to advanced epiphytic forms, because they are native to the most ancient part of South America, the Guyana Shield, and because they have evolved a remarkable range of means for capturing mineral nutrients including carnivory, symbiotic nitrogen fixation, and feeding by ants. The investigators will collect specimens of the estimated 21 species of the genus in Venezuela, Brazil, and Colombia. They will assess genomic relationships among species through analysis of chloroplast DNA. Comparison of these results with study of floral and vegetative traits will permit evaluation of the reliability of traditional anatomical characters in taxonomic classifications. The goal of the research is to understand how the species evolved, how they have adpated to conditions of extreme soil infertility, and how they have dispersed through geological time across the northern range of South America.