Collaborative Research: Analysis of rapidly evolving potassium channels in electric fish

这个项目的目的是了解基因变化如何有助于新的动物信号行为的进化。这个合作项目的研究人员将在来自非洲的被称为桑鱼的弱电鱼类中研究这个问题。该团队之前已经发现了一种由kcna7a基因编码的蛋白质，它经历了激烈的自然选择，允许Mormyrids产生极短的电信号，称为电子器官放电(EOD)。尽管Mormyrids对短EOD脉冲的选择很强，但在200多种Mormyrids中，脉冲持续时间的进化差异很大，而长持续EOD脉冲已经从短持续EOD脉冲的祖先进化了至少三次。该项目的基本假设是，长持续时间的EOD是对kcna 7a基因中的氨基酸替换进行选择的结果。在这个项目中，研究人员将通过检测kcna 7a在二次进化长持续EOD的物种中的生物物理性质来检验这一假说，并进行基于现场的行为研究，以确定导致长持续EOD进化的选择因素。该项目将通过向广泛使用的EFISH基因组学门户网站添加数据产品、完善的功能和工具来增强研究的基础设施，通过持续指导相关的本科生、研究生和博士后助理来促进教与学，并通过继续与机构合作伙伴网络保持富有成效的关系来扩大参与，以从代表不足的群体中招聘有才华的人员，与德克萨斯州奥斯汀的休斯顿-蒂洛森大学合作。21世纪生物学的一个主要目标是了解分子水平的变化如何导致有机体水平的表型变化。尽管在广泛的分类群中解开“表型的分子基础”方面取得了越来越大的进展，但重要的是要维持这样的观点，即较高水平的生物组织的作用力自上而下地塑造表型。在许多系统中，这些因素是众所周知的，但它们与已识别的基因变异的确切联系仍然知之甚少。在电鱼中，影响电表型的选择作用力是已知的，产生它们的基因座被识别，这些基因座中影响功能的特定核苷酸被表征，这些基因座被认为是宏观进化尺度上的选择目标。在具体目标1中，本项目将：确定长EOD脉冲二次进化的生物物理基础，方法是对二次进化长持续期EOD及其具有短存续期EOD的同系物的物种中的kcna 7a进行测序，测量其生物物理性质，利用定点突变检查特定位点的作用，并确定二次进化的长持续期EOD是一次还是多次并行进化。在具体目标2中，研究人员将结合电生理学和计算建模，确定产生长持续EOD的物种是否具有长持续AP和kcna 7a电流的特性是否足以延长它们。在具体目标3中，调查人员将通过在加蓬中西部进行实地研究，确定导致长期使用的EOD演变的选择因素。A调查人员将继续努力，与HBCU合作，扩大代表不足的群体的参与。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。

The purpose of this project is to understand how genetic changes contribute to the evolution of new animal signaling behaviors. The investigators of this collaborative project will study this question in weakly electric fishes from Africa, known as mormyrids. The team has previously discovered a protein, encoded by the gene kcna7a that has undergone intense natural selection mormyrids, which allows mormyrids to produce extremely short electric signals called an electric organ discharge (EOD). Despite the strong selection on mormyrids for brief EOD pulses, the evolution of pulse duration varies dramatically across the more than 200 species of mormyrids, and long duration EOD pulses have evolved at least three times from short-duration EOD pulse ancestors. The underlying hypothesis of this project is that the long-duration EODs are the result of selection acting on amino acid substitutions in the kcna7a gene. In this project, the investigators will test this hypothesis by examining the biophysical properties of kcna7a in species that secondarily evolved long duration EODs, and conduct field-based behavioral studies to determine the selective factors that lead to the evolution of long duration EODs. This project will enhance infrastructure for research by adding data products, refined functionality, and tools to the broadly utilized EFISH Genomics Web Portal, promote teaching and learning by ongoing mentorship of undergraduates, graduate students and postdoctoral associates associated and broaden participation by continuing the productive relationship with a network of institutional partners to recruit talented personnel from underrepresented groups, working with Huston-Tillotson University, a HBCU in Austin, TX.A major goal of 21st century biology is to understand how changes at the molecular level result in phenotypic changes at the organismal level. Despite the growing progress in unraveling the "molecular basis of phenotype" in a wide variety of taxa, it is important to maintain the view that forces at higher levels of biological organization shape phenotypes from the "top down". In many systems, these factors are well known, but their precise connection to identified genetic variants is still poorly understood. In electric fish, the selective forces that influence electric phenotype are known, the loci that produce them are identified, the specific nucleotides within these loci that affect function are characterized, and these loci are known to be targets of selection on macroevolutionary scales. In Specific Aim 1, this project will: determine the biophysical basis of secondary evolution of long EOD pulses by sequencing kcna7a in species that secondarily evolved long duration EODs and their congeners with short duration EODs, measuring their biophysical properties, examining the role of specific sites using site-directed mutagenesis, and determining whether secondarily derived long-duration EODs evolved once or multiple times in parallel. In Specific Aim 2, the investigators will determine whether species that produce long duration EODs have long-duration APs and, and whether properties of kcna7a currents are sufficient to lengthen them, using a combination of electrophysiology and computational modeling. In Specific Aim 3, the investigators will determine the selective factors that lead to the evolution of long duration EODs using by performing field studies in Gabon West-Central Africa. A investigators will continue their efforts to broaden participation of underrepresented groups in partnership with an HBCU.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.