The genetic architecture of local adaptation in a dioecious species: implications for chromosome evolution

这项研究将提供对自然选择如何导致种群分化的更深层次的理解，这是物种形成的第一步，重点是男性和女性之间的不同特征。这项研究的结果将解决选择在男性和女性之间如何变化的基本方面，以及这如何影响基因和染色体的结构。了解这些过程将拓宽我们对生物学一个核心问题的认识：为什么会有这么多不同种类的有机体？这项工作将在科学研究和公共宣传方面培训几名本科生和研究生以及一名博士后学者，并为他们提供建立国际合作的机会。研究人员将与印第安纳州布鲁明顿的科学家、WonderLab科学、健康和技术博物馆的科学家以及坦普尔顿小学的教师合作，制作关于授粉生物学和植物繁殖的公开展示。本研究将以短命、草本、雌雄异株的多年生植物白露蓬为材料，研究其局部适应的遗传结构。研究人员假设，局部适应主要是通过对男性的选择发生的，这不仅导致了男性和女性之间的表型差异，而且局部适应的遗传基础与伪常染色体基因座有关。为了验证这一假设，他们将进行一项为期多年的相互移植实验，对象是来自西班牙和克罗地亚的两个在性别二型性特征方面差异很大的群体。他们还将在温室和田间进行操控实验，以确定：(1)哪些性状与局部适应有关(通过表型选择分析)，以及水可获得性和气温的变化如何影响这种适应(通过水分和温度控制)，(2)雄性是否受到更大的选择以进行分化，以及(3)这些性状中是否存在性别对抗。除了纯群体个体外，在西班牙和克罗地亚种植的F2后代将进一步确定哪些性状和数量性状座位(QTL)是这两个生境之间差异选择的目标。他们将测量差异性状的QTL在多大程度上本质上是性别特有的效应或在两性之间共享，最后，负责适应性特征差异的QTL是否发生在性染色体的假常染色体区域。结果将决定雄性和雌性的哪些性状正在被选择，雄性和雌性之间的对抗选择在多大程度上涉及到适应性种群分化，以及这些基因座在X和Y染色体上的位置。

This study will provide a deeper understanding into how natural selection leads to the divergence of populations, the first step toward speciation, focusing on traits that differ between males and females. The results of this study will address fundamental aspects of how selection varies on males and females and how this affects the structure of genes and chromosomes. Understanding these processes will broaden our knowledge about a central question of biology: Why are there so many different kinds of organisms? The work will train several undergraduate and graduate students, as well as a postdoctoral scholar, in both scientific research and public outreach, and provide them with opportunities to establish international collaborations. The researchers will work with scientists at Bloomington, IN, WonderLab Museum of Science, Health and Technology and with teachers at the Templeton Elementary School to create public displays about pollination biology and plant reproduction. This study will investigate the genetic architecture of local adaptation using the short-lived, herbaceous, dioecious, perennial plant white campion (Silene latifolia). The researchers hypothesize that local adaptation occurs primarily via selection on males, leading not only to phenotypic differences between males and females, but also the genetic basis of local adaptation being associated with pseudoautosomal loci. To test this hypothesis, they will conduct a multi-year reciprocal-transplant experiment using two populations from Spain and Croatia that are highly divergent for sexually dimorphic traits. They will also conduct manipulative experiments in the greenhouse and the field to determine: (1) which traits are involved in local adaptation (via phenotypic-selection analyses), and how variation in water availability and air temperature influences this adaptation (via water and temperature manipulation), (2) whether males are under greater selection to diverge, and (3) whether sexual antagonism exists for any of these traits. In addition to pure-population individuals, F2 progeny planted in both Spain and Croatia will allow further determination of which traits and quantitative trait loci (QTL) are targets of differential selection between the two habitats. They will measure the extent to which QTL for divergent traits are essentially sex specific in their effect or shared between the sexes, and lastly, whether QTL responsible for adaptive trait divergence occur in the pseudoautosomal region of the sex chromosomes. The result will determine which traits of males and females are under selection, the extent to which antagonistic selection between males and females is implicated in adaptive population differentiation, and the extent to which these loci are located on the X and Y chromosomes.