Collaborative: Phylogeny, Character Evolution, and Diversification of Extant Ferns

加州大学伯克利分校的艾伦·史密斯博士与犹他州立大学和芝加哥菲尔德自然历史博物馆的同事合作，正在收集一个主要的数据库，其中包括30多个现存蕨类植物科的代表植物的分子和形态特征，以便构建蕨类植物的整体系统发育框架。在1994年蕨类植物专家研讨会上取得的令人印象深刻的成果的基础上，史密斯和他的同事们正在继续进行一个主要的DNA测序项目，对四个基因进行测序，两个来自叶绿体基因组，两个来自细胞核，这有望为系谱分析提供信息变异。反过来，这个分子数据库将补充从同一蕨类植物的营养和生殖部分提取的传统解剖和形态特征，以分析其DNA，以及用于其分类鉴定和分类的标准特征。明确蕨类植物的系统发育将有助于进一步研究蕨类植物主要类群“水足科”的白垩纪辐射和多样化的特征进化模式和序列，并为科级和属级的分类修订研究奠定基础。利用比较方法，研究人员可以探索相关进化变化的性状之间的关联模式，这可能有助于解释蕨类植物中不同谱系的成功或失败（灭绝）。

9616260 Smith In a three-institution collaboration with colleagues at Utah State University and Chicago's Field Museum of Natural History, Dr. Alan Smith at University of California at Berkeley is amassing a major database of molecular and morphological characters of representatives of the 30 or so families of living ferns, in order to construct an overall phylogenetic framework for ferns. Building upon the impressive results of a 1994 symposium of fern specialists, with an international team that produced preliminary results for this effort (published in 1995), Smith and his colleagues are continuing a major DNA sequencing project for four genes, two from the chloroplast genome and two from the nucleus, that hold promise of yielding informative variation for genealogical analyses. This molecular database in turn is to be supplemented with traditional anatomical and morphological features drawn from the vegetative and reproductive parts of the same ferns analyzed for their DNA, features used standardly in their taxonomic identification and classification. A well-resolved phylogeny for ferns will facilitate future work on the patterns and sequences of character evolution that gave rise to the Cretaceous radiation and diversification of the major group of ferns, the "polypodiaceous" group, and will provide a foundation for family- and genus-level taxonomic revisionary research. Using comparative methods, researchers can explore patterns of association among characters for correlated evolutionary changes, that may help explain the success or failure (extinction) of various lineages within the ferns.