Phylogenetic Analysis of Eurasion Allotetraploid Species of Elymus (Gramineae) Based on Four Molecular Data Sets.

[42619]芝加哥伊利诺斯州大学的Roberta Mason-Gamer博士的研究旨在阐明几个欧洲和亚洲草属物种的进化历史。麦草与小麦、大麦和黑麦一起被归入小麦科。从进化的角度来看，羊草很有趣，因为它复杂的遗传历史。小麦科的遗传最简单的二倍体成员有两套完整的染色体（就像人类一样，每一个亲本各有一套染色体），而羊草类的个体有四套、六套甚至八套完整的染色体，代表了来自两个或更多遗传和进化上不同的祖先的组合基因组。本研究的重点是原产于欧洲和亚洲的四基因组（四倍体）Elymus成员，并直接建立在早期对北美四倍体Elymus物种的研究基础上。这项研究的目的是利用来自四种不同分子标记的DNA序列数据，阐明18种复杂欧亚物种的进化史。更具体地说，目标是：(1)确定每个物种的二倍体母系和父系祖先；(2)评估羊草的遗传多样性模式是否与广泛的地理模式相对应，还是与先前观察到的外部可见的形态变异模式相对应。当这些物种的数据与北美四倍体的现有数据相结合时，这项研究将包括迄今为止使用详细的分子系统发育方法检查的最大多倍体群体。多倍体的研究与了解地球上开花植物的非凡多样性有关，因为多达一半的开花植物物种是多倍体起源的。多倍体不仅代表了植物物种形成的主要机制，而且我们的一些最重要的农作物也是多倍体，包括苜蓿、油菜、棉花、咖啡、十字花科蔬菜、土豆、大豆、烟草、小麦和许多其他植物。因此，多倍体形成的机制和伴随多倍体的遗传变化在许多研究领域引起了植物科学家的广泛兴趣。这里描述的进化研究为多倍体的许多其他方面的详细探索奠定了必要的基础。除了提供对Elymus复杂历史的深入了解外，该项目还将以两种方式支持伊利诺伊大学芝加哥分校的学生教育。首先，两名研究生将获得资助。他们将深入参与基因数据的收集、分析和解释。无论他们从这些经验中获得了什么方法和思想，都将直接丰富自己的论文研究。第二，本科生的参与将是完成项目的重要组成部分。补助金提供勤工俭学的工资，也支持那些希望通过完成研究项目获得课程学分的学生的用品费用。本科生将学习许多广泛适用的实验室技术，包括DNA分离、基因扩增和DNA测序。

0426194Mason-Gamer Research by Dr. Roberta Mason-Gamer of the University of Illinois-Chicago is designed to clarify the evolutionary history of several European and Asian species in the grass genus Elymus. Elymus is classified within the wheat tribe, Triticeae, along with wheat, barley, and rye. From an evolutionary standpoint, Elymus is interesting because of its complex genetic history. While the genetically simplest, or diploid, members of the Triticeae have two complete sets of chromosomes (one set from each parent, just as in humans), Elymus individuals have four, six, or even eight complete sets, representing the combined genomes from two or more genetically and evolutionarily distinct ancestors. This research focuses on the four-genome (tetraploid) members of Elymus that are native to Europe and Asia, and builds directly upon earlier research on the tetraploid Elymus species of North America. The objective of the research is to clarify the evolutionary history of 18 of these complex Eurasian species using DNA sequence data from four different molecular markers. More specifically, the goals are to: (1) identify the diploid maternal and paternal progenitors of each species, and (2) assess whether patterns of genetic diversity within Elymus correspond either to broad geographic patterns, or to previously observed patterns of outwardly visible morphological variation. When data from these species are combined with existing data from the North American tetraploids, this research will encompass the largest group of polyploids examined to date using detailed molecular phylogenetic methods. Studies of polyploids are relevant to understanding the extraordinary diversity of flowering plants on earth, since as many as half of all flowering plant species are of polyploid origin. Not only does polyploidy represent a major mechanism of plant speciation, but some of our most important crop plants are polyploid, including alfalfa, canola, cotton, coffee, cruciferous vegetables, potatoes, soybeans, tobacco, wheat, and many others. Thus, mechanisms of polyploid formation and the genetic changes that accompany polyploidy are of broad interest to plant scientists in many fields of research. Evolutionary studies such as the one described here lay the necessary groundwork for detailed explorations of many other facets of polyploidy. In addition to providing insights into the complicated history of Elymus, the project will support student education at the University of Illinois at Chicago in two ways. First, two graduate students will be supported by the grant. They will be deeply involved with the collection, analysis, and interpretation of genetic data. Whatever they gain from this experience in terms of methods and ideas will directly enrich their own thesis research. Second, undergraduate student participation will be an important part of completing the project. The grant provides work-study wages, and also supports the cost of supplies for students who wish to receive course credit for completing research projects. Undergraduates will learn many broadly applicable laboratory techniques, including DNA isolation, gene amplification, and DNA sequencing.