DISSERTATION RESEARCH: Assessing the Evolutionary Significance of Recurrent Horizontal Gene Transfer of a Chimeric Photoreceptor in Ferns

这项研究将提供一个更深入的了解蕨类植物的系统学和基因，使他们能够在阴凉的栖息地生长。新色素是一种新型的嵌合光感受器，它将红色和蓝色光感受器融合到一个基因中，这种新色素的存在与蕨类植物在弱光条件下茁壮成长的能力有关。尽管它在适应中具有潜在的重要性，但新色素的进化仍未被探索。本研究将探讨新色素的演化，并验证该基因的分布是蕨类植物间重复性水平基因转移的结果这一假设。该奖项将支持一名女博士生和本科生研究人员在不同的分子和系统方法方面的研究和培训。水平基因转移（HGT）在原核生物中很常见，通常是适应和进化的关键驱动力。然而，大多数记录的植物到植物的HGT的例子涉及线粒体DNA和/或寄生虫宿主转移;只有少数情况下，包括功能性核基因，甚至更少的可能适应性的影响。因此，植物到植物的HGT通常被忽视，作为一个值得注意的因素在植物进化。本研究的目的是使用有针对性的新一代测序的neochrome从不同的蕨类植物物种，以进一步阐明的频率和时间的似乎大量的neochrome水平基因转移事件在蕨类植物。由于neochrome可能发挥了重要作用，促进辐射的蕨类植物在低光环境下，这项研究具有重要意义，更好地了解植物到植物HGT的进化意义。

This study will provide a deeper understanding of the systematics of ferns and the genes that allow them to grow in shady habitats. The presence of neochrome -- a novel chimeric photoreceptor that fuses red-sensing and blue-sensing photoreceptors into a single gene -- is linked to the ability of ferns to thrive in low-light conditions. Despite its potential importance in adaptation, the evolution of neochrome has remained unexplored. This study will investigate the evolution of neochrome and test the hypothesis that the distribution of the gene is the result of recurrent horizontal gene transfer among ferns. This award will support the research and training of a female doctoral student and undergraduate researchers in diverse molecular and systematic methods. Horizontal gene transfer (HGT) is common in prokaryotes and is often a key driver of adaptation and evolution. However, most documented examples of plant-to-plant HGT involve mitochondrial DNA and/or parasite-host transfers; only a handful of cases include functional nuclear genes, and even fewer have possible adaptive implications. Consequently, plant-to-plant HGT generally has been overlooked as a noteworthy factor in plant evolution. The aim of this research is to use targeted next-generation sequencing of neochrome from diverse fern species to further elucidate the frequency and timing of the seemingly large number of neochrome horizontal gene transfer events in ferns. Because neochrome may have played a major role in promoting the radiation of ferns under low-light environments, this study has important implications for better understanding the evolutionary significance of plant-to-plant HGT.