DISSERTATION RESEARCH: Understanding the Role of Chromosomal Inversions in Life History Divergence and Local Adaptation in Mimulus

论文研究：了解染色体倒位在酸浆菌生活史分歧和局部适应中的作用

• 批准号: 1501758
• 负责人: John Willis
• 金额: $ 2.07万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1501758&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Understanding; Role; Chromosomal

The goal of this project is to gain a better understanding of the role of gene arrangements on chromosomes in maintaining genetic diversity, which is fundamental to the process of evolution. Beyond adding to basic knowledge of evolution, these results have important implications for crop breeding, especially when crops occur in the presence of closely related non-crop species. The study will focus on monkeyflower, Mimulus guttatus, an herbaceous wildflower that is distributed predominantly in the Pacific Northwest. It occurs both as perennial and annual forms, which are distinct and locally adapted to their respective habitats. Through the use of genetic tools, the researchers will discover the bases of the differences between those forms and test hypotheses about how gene arrangements control evolution.The researchers will use genetic tools to dissect a chromosomal inversion which varies between annual and perennial ecotypes of Mimulus guttatus. This inversion is strongly associated with life history expression, and has been shown to influence performance in nature significantly. Previous QTLs mapping has found that a large proportion of the genetic variance associated with life history maps to a large pericentric chromosomal inversion that separates the two ecotypes. However, since recombination is suppressed between inverted and collinear portions of a chromosome when found in a heterozygote, mapping within the inversion is impossible in this species pair. Using classical QTLs mapping, as well as NIL lines, the researchers will: (1) create a genome-wide map of life history divergence under multiple conditions, (2) test how the inversion contributes to life history divergence in the field, and (3) examine how selection acts on alleles within the inversion. The researchers will test whether the inversion has captured standing genetic variation for life history traits, and thus has potentially swept to fixation by indirect selection due to its recombination suppression properties. This work will help elucidate the mechanism by which inversions contribute to local adaptation, and ultimately, how inversions can maintain genetic diversity despite maladaptive gene flow.

这个项目的目标是更好地了解染色体上的基因排列在维持遗传多样性方面的作用，这是进化过程的基础。除了增加进化的基本知识外，这些结果还对作物育种有重要的影响，特别是当作物出现在密切相关的非作物物种存在的情况下。这项研究将集中在猴花，Mimulus guttatus，一种主要分布在太平洋西北部的草本植物野花。它以多年生和一年生的形式出现，这些形式是不同的，并在当地适应了各自的栖息地。通过使用遗传工具，研究人员将发现这些形式之间差异的基础，并测试关于基因安排如何控制进化的假说。研究人员将使用遗传工具解剖一年生和多年生生态型点滴水母的染色体倒位。这种倒置与生活史表达密切相关，并已被证明在自然界中对表现有显著影响。先前的QTL定位发现，与生活史相关的遗传变异的很大一部分映射到区分这两个生态型的大的着丝粒染色体倒位。然而，由于当在杂合子中发现染色体的倒置部分和共线部分之间的重组被抑制时，在该物种对中不可能在倒置中进行映射。使用经典的QTL作图以及近等位基因系，研究人员将：(1)创建多个条件下的生活史分歧的全基因组图谱，(2)测试倒位如何导致田间生活史的分歧，以及(3)检验选择如何对倒位中的等位基因起作用。研究人员将测试这种倒位是否捕捉到了生活史特征的长期遗传变异，因此由于其重组抑制特性，可能已经通过间接选择达到固定。这项工作将有助于阐明倒置有助于局部适应的机制，并最终阐明倒置如何在不适应基因流的情况下保持遗传多样性。