Genealogical Studies of Polyploidy Using Tetraploid Zea Perennis (Poacease) as a Model System

9815855Gaut多倍体是一种使有机体的染色体内容倍增的机制，这一过程在植物中尤为重要。大约70%的植物具有多倍体起源，小麦和棉花等主要农作物的农业生产力归功于最近发生的多倍体事件。然而，人们对多倍体基因的进化命运知之甚少，这是我们对植物遗传学理解的一个巨大差距。本研究以玉米的近缘多倍体玉米(Zea Perennis)为材料，研究其遗传变异。这项研究的目的是：i)测量多倍体基因的遗传变异，ii)分析遗传变异的模式，以确定作用于重复基因的群体作用力，以及iii)确定多倍体过程发生一次还是多次。遗传变异将通过对来自30个个体的3个基因的DNA测序来衡量，这些基因代表了玉米及其推定的祖先--双花玉米。该项目的数据将与之前对玉米和其他野生近缘关系的研究数据进行分析。作为此类研究的第一次，这项拟议的工作有可能为一系列广泛的问题提供独特和一般性的见解，如多倍体形成的方式、多倍体基因的遗传模式，以及重组、突变和自然选择等进化过程在塑造多倍体遗传多样性方面的相对重要性。H：\POPIO\ASTERCTS\fY1999\9815855(高特摘要)

9815855GautPolyploidy is a mechanism that multiplies the chromosomal content of an organism, a process that is particularly important in plants. Approximately 70% of all plants have a polyploid origin, and major crops like wheat and cotton owe their agricultural productivity to recent polyploid events. Little is known, however, about the evolutionary fate of polyploid genes, and this is a broad gap in our understanding of plant genetics. This study focuses on genetic variation in Zea perennis, a polyploid that is a close relative of maize (corn). The goals of the study are to: i) measure genetic variation in polyploid genes, ii) analyze the pattern of genetic variation to determine the population forces acting on duplicated genes, and iii) determine whether the polyploid process occurred once or multiple times. Genetic variation will be measured by sequencing DNA of 3 genes from 30 individuals representing Zea perennis and its presumed ancestor, Z. diploperennis. The data from this project will be analyzed with data from previous studies of maize and other wild relatives.As the first study of its kind, the proposed work has the potential to provide unique and general insights into a broad array of issues, such as the way polyploids form, the mode of inheritance of polyploid genes, and the relative importance of evolutionary processes like recombination, mutation and natural selection in shaping genetic diversity in a polyploid. H:\popbio\abstracts\fy1999\9815855 (Gaut abstract)