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

[98509] doyle and Ingram Tef （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Eragrostis中的进化起源尚不清楚。研究生阿曼达·英格拉姆在康奈尔大学导师杰夫·道尔博士的指导下提出了这项研究计划，其主要目标是调查之前提出的tef祖先之间的进化关系，以确定该作物祖先的现存代表，并阐明这种大型但研究较少的草属之间的关系。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众多多倍体tef（结合来自不同亲本的整套染色体）的比较遗传分析的特征来源。核基因的数据将有助于确定两个祖先物种，而叶绿体位点将有助于确定tef的母系祖先。对这些数据的分析还将包括其他分类群，以开始对这种草属的主要谱系之间的关系产生假设，该属目前有350个已命名的物种。该项目的另一个组成部分将是通过与野生祖先的比较来研究tef驯化过程中的形态学变化。这些研究将有助于确定目标基因，为未来研究驯化过程中涉及的遗传变化提供帮助。tef及其野生近缘种的遗传多样性也将通过使用高度可变的分子标记进行检查。这些数据也将有助于确定不同品种的家谱结构，并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.