SG: The adaptive (and maladaptive) consequences of non-additive genetic variation

了解生物体如何适应环境的遗传基础和潜在局限性在生物学的许多领域都非常重要。例如，这种知识可以改进作物育种，并可以改进对本地物种和农艺物种对气候变化的反应的预测。目前关于适应遗传学的知识大多局限于遗传变异的一个子集，其中基因的不同拷贝（等位基因）对生存和繁殖的影响是累加的，可以简单地加在一起。然而，等位基因对生物体的影响可能取决于同一基因或不同基因的其他等位基因的存在，以及环境条件。其中一个例子是所谓的杂种优势，这通常发生在不同品系的植物交配在一起，并导致杂交后代具有更好的生存和更好的种子生产比任何一个亲本品系。这项研究使用了一组独特的遗传资源来量化这些非累加效应对生存和种子生产的贡献。 将与K-12学生开展外联活动，主题涉及面对气候变化的适应和适应不良。尽管近世纪来人们一直在研究适应性的遗传学，但我们对非加性遗传变异对适应性的贡献、尽管存在适应不良的基因座，但适应性在多大程度上仍然存在，以及这种平衡如何随着环境的变化而改变等问题知之甚少。这项研究将确定杂种优势（杂种优势）和杂种优势的环境相互作用的健身的遗传基础，量化的上位性在适应性分化的作用，并确定在何种程度上拮抗基因座有助于超亲分离在当地适应人群之间的杂交。基础工作映射的遗传基础的长期健身的两个生态型的拟南芥从意大利和瑞典在本地网站牵连一个复杂的遗传基础，包括上位性，适应性和适应不良的等位基因的混合物，并在瑞典的健身越界隔离。优势在这些生态型之间的杂交中有助于杂种优势，并且有限的遗传变异和高杂种优势是北方群体的特征。该研究将利用一组近等基因系（NIL）来产生纯合、杂合和组合渐渗片段。为了研究杂种优势，上位性，和添加剂互补的健身，这些线的健身组件将在生长室中进行分析编程，以模拟本地环境，设计和优化超过十年的网站水平的气候和健身数据。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding the genetic basis, and potential limitations, of how organisms adapt to their environment is fundamentally important in many areas of biology. For example, such knowledge can improve crop breeding and can improve predictions about responses to climatic variability in both native and agronomic species. Current knowledge about the genetics of adaptation is mostly limited to a subset of genetic variation, where the effects of different copies (alleles) of a gene on survival and reproduction are additive and can simply be summed together. However, the effects of alleles on the organism can depend on the presence of other alleles for the same gene or different genes, and on environmental conditions. One example of this is called hybrid vigor, which often occurs when mating together plants of different strains, and results in hybrid offspring that have better survival and better seed production than either parent strain. The proposed research uses a unique set of genetic resources to quantify the contribution of these non-additive effects on survival and seed production. Outreach activities will be conducted with K-12 students on topics related to adaptation and maladaptation in the face of climate change. Despite nearly a century of work on the genetics of adaptation, we know little about the contribution of non-additive genetic variation to adaptation, the extent to which adaptation exists despite maladaptive loci, and how that balance may shift with environmental change. This research will determine the genetic basis of heterosis (hybrid vigor) and heterosis-by-environment interactions for fitness, quantify the role of epistasis in adaptive differentiation, and determine the extent to which antagonistic loci contribute to transgressive segregation in crosses between locally-adapted populations. Foundational work mapping the genetic basis of long-term fitness of two ecotypes of Arabidopsis thaliana from Italy and Sweden at the native sites implicated a complex genetic basis, including epistasis, a mixture of adaptive and maladaptive alleles, and transgressive segregation for fitness in Sweden. Dominance contributes to heterosis in a cross between these ecotypes, and limited genetic variation and high heterosis characterize northern populations. The research will leverage a panel of Near Isogenic Lines (NILs) to produce homozygous, heterozygous, and combinatorial introgression segments. To investigate heterosis, epistasis, and additive complementation for fitness, fitness components of these lines will be assayed in growth chambers programmed to simulate the native environments, designed and optimized with over a decade of site level climate and fitness data. Training will be provided for a graduate and undergraduate student who will also participate in K-12 outreach activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.