Research Starter Grant: Genome Evolution in Polyploid Helianthus (Asteraceae)

这是为Sheri博士提供的研究启动基金，她是美国国家科学基金会生物信息学博士后研究奖学金的获得者。了解物种形成的遗传学仍然是进化生物学的一个核心问题。作为美国国家科学基金会生物信息学博士后，研究者利用向日葵EST数据库鉴定了几种二倍体向日葵的正选择基因。目前的奖金支持这项研究的下一阶段，特别是了解多倍体向日葵中这些相同基因的进化史。研究者计划克隆和测序在二倍体向日葵物种中发现的中性、正、负进化的基因子集。将对这些克隆进行测序，并检查任何可变拷贝的选择类型。由于向日葵辐射最近，这些分析有望阐明多倍体内等位基因的分化率。本研究将为进化与生物信息学领域的本科生提供研究机会。在教育之外，这项研究的影响是基础的和应用的。虽然已经做了很多工作来了解二倍体物种形成的遗传学，但很少有研究关注多倍体物种形成。这一结果将有助于我们对多倍体基因组的分子进化和向日葵物种形成遗传学的理解。此外，其中一个多倍体物种被研究是耶路撒冷洋蓟（Helianthus tuberosus），两种重要的农业向日葵物种之一。虽然这种植物是一种重要的作物，但它也是一种入侵杂草。这项研究将通过提供各种重要向日葵基因命运的遗传分析，增加我们对这一特定物种进化史的理解。

This is a Research Starter Grant provided for Dr. Sheri who was a recipient of the NSF Postdoctoral Research Fellowship in Biological Informatics. Understanding the genetics of speciation remains a central question in evolutionary biology. As an NSF Postdoctoral fellow in Biological Informatics, the investigator utilized an EST database for sunflower to identify positively selected genes in several diploid sunflowers. The current award support the next phase of this research, specifically to understand the evolutionary history of these same genes in polyploid sunflowers. The investigator plans to clone and sequence a subset of genes found to be evolving neutrally, positively, and negatively in diploid sunflower species. These clones will be sequenced and any variable copies will be examined for the types of selection acting on them. Due to the recency of the sunflower radiation, these analyses are expected to shed light on the rate of divergence among alleles within polyploids. This research will provide research opportunities for undergraduate students in the field of evolution and bioinformatics. Beyond education, the impact of the research is both basic and applied. While much work has been done to understand the genetics of diploid speciation, very little research has focused on polyploid speciation. The results will enhance our understanding of the molecular evolution of polyploid genomes as well as sunflower speciation genetics. Furthermore, one of the polyploidy species to be examined is the Jerusalem artichoke (Helianthus tuberosus), one of two agriculturally important sunflower species. While this species is an important crop, it is also an invasive weed. The research will increase our understanding of the evolutionary history of this particular species by providing genetic analyses of the fates of a variety of important sunflower genes.