International Research Fellowship Program: Origins of Polyploidy in Achillea Millefolium

[202729]拉姆西国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Justin M. Ramsey博士与加拿大安大略省圭尔夫大学的Brian C. Husband博士开展为期24个月的研究。本项目将调查一种具有四倍体和六倍体种群的本土野花——千叶阿喀琉斯（Achillea millefolium）。最近的研究记录了六倍体基因型对干旱环境的局部适应。本研究扩展了这些研究，以解决以下问题：(1)多倍体建立的动力学是什么，遗传和生态因素如何影响这一过程？(2)北美菊苣多倍体的系统发育历史如何？基于生活史模型（从配子到种子，种子到幼苗，幼苗到成体，成体到配子）的数值模拟将追踪四倍体种群中六倍体突变体的命运，并确定六倍体种群建立和持续存在的条件。以前的经验数据将用于参数化模拟。扩增片段长度多态性（AFLP）遗传标记和DNA序列数据的系统发育分析将在区域和大陆地理尺度上进行，以量化当地六倍体形成的发生率以及六倍体在物种范围内的成功建立。这项多方面的研究将阐明多倍体进化的机制、生态意义和模式。丈夫在分子标记，群体遗传学，生态学和进化的定量方法方面有很强的背景。他开发了多倍体研究的定量方法。

0202729RamseyThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Justin M. Ramsey to work with Dr. Brian C. Husband at the University of Guelph, Ontario, Canada.This project will involve the investigation of Achillea millefolium (asteraceae), a native wildflower with tetraploid and hexaploid populations. Recent studies document the local adaptation of hexaploid genotypes to xeric environments. This research extends those investigations to address the following questions: (1) What are the dynamics of polyploid establishment, and how do genetic and ecological factors influence this process?; and (2) What is the phylogenetic history of polyploidy in North American Achillea? Numerical simulations based on a life-history model (transitions from gamete to seed, seed to seedling, seedling to adult, and adult to gamete) will track the fate of hexaploid mutants in tetraploid populations, and identify the conditions in which hexaploid populations establish and persist. Previous empirical data will be used to parameterize the simulation. Phylogenetic analyses of Amplified Fragment Length Polymorphisms (AFLP) genetic markers and DNA sequence data will be conducted at both regional and continental geographic scales to quantify local incidences of hexaploid formation as well as successful establishments of hexaploids over the species range. This multi-faceted research will elucidate the mechanisms, ecological significance, and patterns of polyploid evolution.Dr. Husband has a strong background in molecular markers, population genetics, and quantitative methods in ecology and evolution. He has developed quantitative approaches in polyploidy research.