Dissertation Research: Systematics of Ulvaceae (Ulvales, Chlorophyta) using Nuclear and Chloroplast DNA Sequences

Waaland和Hayden尽管在过去十年中对陆地植物进行了大量基于DNA的系统和系统发育研究，但一些主要的绿色植物谱系仍有待探索。绿藻科绿藻门包含许多这样的类群，包括石榴科(Ulvales，Ulvophyceae)。石榴科是一种形态简单、广布的海洋和淡水环境中的宏观藻类。该家族的两个成员，石龙藻和蜈蚣属，是最熟悉的绿色海藻属。作为常见的船舶污垢藻类，它们也经常被牵连到“绿潮”中，这是由于水华事件后它们的生物量过度积累造成的。除了直接扼杀海洋动物外，绿潮腐烂的生物量释放的硫化氢还可能给人类和海洋生物带来重大的健康问题。形态的简单性和表型的可塑性阻碍了系统学家过去试图在物种丰富的石榴属和蜈蚣属以及这些属和该科其他属之间诊断自然归类的努力。研究生Hillary Hayden在J.Robert Waaland博士的指导下，将研究这些属的分类亲缘关系和系统关系，重点是来自核和叶绿体基因的新DNA序列数据，用于比较分析物种之间的突变差异。提高对石榴科系统学的了解对于解释绿潮现象和识别非本土物种是必要的。此外，生物学家将受益于更好地了解这些类群之间的系统发育关系，以及在非常接近的藻类群之间表现出的表型变化的复杂性。

0073169Waaland and Hayden Despite numerous DNA-based systematic and phylogenetic studies of land plants in the past decade, some major green plant lineages await exploration. The green algal division Chlorophyta contains many such groups, including the Ulvaceae (Ulvales, Ulvophyceae). Ulvaceae are morphologically simple cosmopolitan, macroscopic algae of marine and freshwater environments. Two members of the family, Ulva and Enteromorpha, are among the most familiar green seaweed genera. Common as ship fouling algae, they also are often implicated in "green tides" which result from excessive accumulations of their biomass following a bloom event. In addition to direct smothering of marine fauna, hydrogen sulfide released from the decaying biomass of green tides can present major health concerns for humans and marine communities. Morphological simplicity and phenotypic plasticity have thwarted pastattempts by systematists to diagnose natural groupings within the species-rich genera Ulva and Enteromorpha as well as among these and other genera inthe family. Graduate student Hillary Hayden, directed by Dr. J. Robert Waaland, will be studying the taxonomic affinities and systematic relationships of these genera, with an emphasis on new DNA-sequence data from both nuclear and chloroplast genes, for comparative analyses of mutational differences among the species. An improved understanding of Ulvaceae systematics is necessary for interpreting green tide phenomena and recognizing non-indigenous species. Further, biologists will benefit from a better understanding of phylogenetic relationships among these taxa and the complexity of phenotypic changes exhibited among a very closely related group of algae.