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

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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.