Dissertation Research: The Origins of Polyploid Eragrostis tef (Poaceae): Phylogeny, Genetic Diversity, and Infraspecific Phylogeography

画眉草（Eragrostis tef）是一种主要生长在埃塞俄比亚的一年生谷类作物，其在草属画眉草中的进化起源尚不清楚。 研究生阿曼达·英格拉姆（Amanda Ingram）在康奈尔大学顾问杰夫·多伊尔（Jeff Doyle）博士的指导下提出的这项研究的主要目标是调查之前提出的茶黄素祖细胞之间的进化关系，以识别该作物祖细胞的现存代表并阐明关系。在这个庞大且研究不足的禾本科属中。他们将使用来自各种基因座的DNA序列数据，包括低拷贝核基因和叶绿体基因座，作为可能的二倍体祖先分类群和多倍体tef（它结合了来自不同亲本的整套染色体）的众多加入的比较遗传分析的特征来源。 来自核基因的数据将有助于识别这两个祖先物种，而叶绿体基因座将有助于识别tef的母系祖先。 其他分类群也将包括在这些数据的分析，开始产生在这个草属，目前有350个命名的物种的主要谱系之间的关系的假设。本计画的另一个组成部分将是通过与其野生祖先的比较，来研究tef在驯化过程中的形态变化。 这些研究将有助于确定未来调查驯化过程中涉及的遗传变化的靶基因。 通过使用高度可变的分子标记，还将检查tef及其野生近缘种的遗传多样性。 这些数据也将有助于确定不同茶籽栽培品种的系谱结构，这可能有助于确定这一重要作物的驯化中心和多样性，包括在未来育种工作中可能具有价值的遗传多样性。

0098509Doyle and Ingram Tef (Eragrostis tef) is an annual cereal crop grown primarily in Ethiopia whose evolutionary origins within the grass genus Eragrostis are unknown. The proposed research by graduate student Amanda Ingram with guidance from adviser Dr. Jeff Doyle at Cornell University has the primary goal of investigating the evolutionary relationships among previously proposed progenitors of tef to identify extant representatives of the crop's progenitors and to elucidate relationships within this large and poorly investigated genus of grasses. They will be using DNA sequence data from a variety of loci, including low-copy nuclear genes and a chloroplast locus, as sources of characters for the comparative genetic analyses of the likely diploid progenitor taxa and of numerous accessions of polyploid tef (which combines whole sets of chromosomes from different parents). The data from the nuclear genes will help identify both progenitor species, while the chloroplast loci will help identify the maternal progenitor of tef. Additional taxa will also be included in the analysis of these data to begin generating hypotheses of relationships among major lineages in this grass genus, which currently has 350 named species. Another component of this project will be investigating the morphological changes involved in the domestication of tef through comparisons with its wild progenitors. These studies will be useful in helping identify target genes for future investigations into the genetic changes involved in the domestication process. Genetic diversity within tef and its wild relatives will also be examined through the use of highly variable molecular markers. These data will also be helpful in determining the genealogical structure of various tef cultivars, and this may helpidentify the center of domestication and diversity of this important crop, including genetic diversity of possible value in future breeding work.