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促进新的动物信号行为的进化。这个合作项目的研究人员将在非洲的弱电鱼（mormords）中研究这个问题。研究小组之前发现了一种蛋白质，由基因kcna7a编码，这种蛋白质经历了激烈的自然选择，使mormords产生极短的电信号，称为电器官放电（EOD）。尽管mordmord对短脉冲EOD有强烈的选择，但脉冲持续时间的进化在200多种mordmord中差异很大，长脉冲EOD脉冲从短脉冲EOD脉冲祖先至少进化了三次。本项目的基本假设是，长时间的eod是选择作用于kcna7a基因的氨基酸取代的结果。在该项目中，研究人员将通过检查次生演化出长时间eod的物种中kcna7a的生物物理特性来验证这一假设，并进行基于现场的行为研究，以确定导致长时间eod演化的选择因素。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、改进功能和工具来增强研究基础设施，通过对本科生、研究生和博士后助理的持续指导来促进教学和学习，并通过继续与机构合作伙伴网络建立富有成效的关系来扩大参与，从代表性不足的群体中招募有才能的人员。21世纪生物学的一个主要目标是了解分子水平的变化是如何导致生物体水平的表型变化的。尽管在揭示各种分类群的“表型的分子基础”方面取得了越来越大的进展，但重要的是要保持这样一种观点，即在较高水平的生物组织中，力量是“自上而下”塑造表型的。在许多系统中，这些因素是众所周知的，但它们与已确定的遗传变异的确切联系仍然知之甚少。在电鱼中，影响电表型的选择力是已知的，产生它们的基因座被鉴定，这些基因座中影响功能的特定核苷酸被表征，并且这些基因座已知是宏观进化尺度上选择的目标。在具体目标1中，该项目将：通过对二级进化出长持续时间爆炸物及其短持续时间爆炸物同系物的物种的kcna7a进行测序，确定长持续时间爆炸物脉冲二级进化的生物物理基础，测量其生物物理特性，使用位点定向诱变技术检查特定位点的作用，并确定二级衍生的长持续时间爆炸物是一次进化还是多次并行进化。在具体目标2中，研究人员将利用电生理学和计算模型的结合，确定产生长时间eod的物种是否具有长时间的ap和，以及kcna7a电流的特性是否足以延长它们。在具体目标3中，研究人员将通过在加蓬中西部非洲进行实地研究，确定导致长期使用的排爆装置演变的选择性因素。A调查人员将继续努力与HBCU合作，扩大代表性不足群体的参与。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.