Evaluating the Cost of Domestication in Sunflower

这一行动为NSF国家植物基因组计划2018财年生物学博士后研究奖学金提供了资金。该奖学金支持在东道主实验室为该研究员制定的研究和培训计划，该研究员还提出了扩大生物学参与度的计划。为艾米丽·迪特马尔博士提供的这项研究和培训计划的标题是《评估向日葵驯化的成本》。该奖学金的主办机构是佐治亚大学和明尼苏达大学，赞助科学家是约翰·伯克博士和彼得·莫雷尔博士。所有生物体的基因组中都存在有害突变。最近的证据表明，农作物基因组比它们的野生近亲拥有更多的有害突变(即突变负载)。这种突变负荷可能是由驯化过程本身引起的，驯化过程的特征通常是遗传多样性的减少和对农艺感兴趣的性状的强烈选择。本项目旨在了解栽培向日葵中突变负载的原因和后果。这项研究的结果将提供有关驯化相关过程如何增加有害变异以及总体突变负载对作物表现的影响的知识。培训目标包括基因组学和基因组数据分析的计算培训。更广泛的影响包括为K-12学生制定关于作物进化和遗传变异的课程计划。通过确定有害突变的全基因组分布，以及通过比较优良品种和历史地方品种的突变负荷，将推断选择性扫描和遗传漂移对向日葵有害变异积累的相对重要性。这些有害的变异将使用计算方法来识别，这些方法基于系统发育序列保守的程度来估计有害影响。这项研究将使用数百个向日葵栽培品系的性能数据来测试这些方法的解释能力，以确定已识别的有害变异对性能变化的解释能力。这个项目的一个全新的组成部分是，它将调查有害变异的影响是否在紧张的环境中升高。来自野生物种的证据表明，有害突变有时在压力下会产生更大的影响，但环境与作物突变负载的相互作用程度迄今尚未被探索。这项研究的结果将几乎完全集中在公开可用的数据上，将通过出版物、在会议上的陈述分享，软件、代码和分析将通过GitHub获得。关键词：驯化、系统发育分析、种群基因组学、向日葵、突变负荷、有害突变、植物生物压力该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This action funds an NSF National Plant Genome Initiative Postdoctoral Research Fellowship in Biology for FY 2018. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Dr. Emily Dittmar is "Evaluating the Cost of Domestication in Sunflower". The host institutions for the fellowship are the University of Georgia and the University of Minnesota, and the sponsoring scientists are Drs. John Burke and Peter Morrell.Deleterious mutations are present in the genomes of all organisms. Recent evidence suggests that crop genomes harbor a greater number of deleterious mutations (i.e. mutational load) than their wild relatives. This mutational load may be caused by the process of domestication itself, which is often characterized by a reduction in genetic diversity and strong selection for traits of agronomic interest. This project aims to understand the causes and consequences of mutational load in cultivated sunflower. Results from this study will provide knowledge about how domestication-related processes increase deleterious variants and the effects of overall mutational load on crop performance. Training objectives include genomics and computational training in the analysis of genomic data. Broader impacts include developing lesson plans about crop evolution and genetic variation for K-12 students.The relative importance of selective sweeps versus genetic drift on the accumulation of deleterious variants in sunflower will be inferred through a determination of the genome-wide distribution of deleterious mutations and by comparing mutational load in elite cultivars to that of historical landrace varieties. These deleterious variants will be identified using computational approaches that estimate deleterious effects based on the degree of phylogenetic sequence conservation. This study will test the explanatory power of these methods using performance data from hundreds of cultivated sunflower lines to determine how well the identified deleterious variants explain variation in performance. A completely novel component to this project is that it will investigate whether the effects of deleterious variants are elevated in stressful environments. Evidence from wild species show that deleterious mutations sometimes have greater effects under stress, but the degree to which the environment interacts with mutational load in crops has so far been unexplored. Results from this research which will focus almost exclusively on publicly available data will be shared through publications, presentations at conferences, and software, code and analyses will be accessible through GitHub. Keywords: domestication, phylogenetic analysis, population genomics, sunflower, mutational load, deleterious mutations, plant biotic stressThis 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.