RUI: Understanding the role of duplicate Hox genes in the evolution of novelty by investigating patterns of molecular evolution and functional divergence in a basal ray-finned fish

进化生物学中最耐人寻味的话题之一是什么类型的基因变化导致表型多样性的问题。将在该项目中检验的中心假设是，基因复制在脊椎动物新特征的进化中发挥了重要作用，更具体地说，在白对虾细长的吻部。在密西西比河流域的浑浊水域中，美国白鳍鱼靠其细长的裙部生存--这是一种夸张的、具有电感官能力的新奇特征。这种极具魅力的生物体属于一个具有动态基因组复制历史的目，数据表明，在白鳍鱼中发生了独立的基因组复制。基因复制被认为是具有新功能和相关表型新颖性的基因产生的主要机制，但导致重复基因最初保留的进化过程尚未被很好地理解。一个名为Hox基因的基因家族与人体平面特征的进化有关。然而，以往关于HOX基因在鱼头和鳍发育过程中的表达的研究并没有考虑到这一点。这个项目将研究白对虾复制的HOX基因的分子进化和功能差异的各个方面。这项拟议的工作意义重大，因为它通过维持最多样化的脊椎动物群体--鳍鱼--的重复基因，确定了与新结构进化相关的遗传路径。这项工作具有重要而广泛的影响，因为它有助于旧金山州立大学培养代表不足的少数族裔和女性学生，旧金山州立大学是一所主要为少数族裔学生服务的本科生机构。此外，这项研究的结果将被注入旧金山州立大学的本科课程。

One of the most intriguing topics in evolutionary biology is the question of what types of genetic changes are responsible for generating phenotypic diversity. The central hypothesis that will be tested in this project is that gene duplication has played an important role in the evolution of novel features in vertebrates, more specifically in the elongated rostrum in the paddlefish. The American paddlefish makes its living in the murky waters of the Mississippi River Basin with its elongated rostrum - an exaggerated novel feature with electrosensory capabilities. This charismatic organism belongs to an order with a dynamic genome duplication history, and data indicate that an independent genome duplication occurred in paddlefish. Gene duplication is regarded as the predominant mechanism by which genes with new functions and associated phenotypic novelties arise, but the evolutionary processes contributing to the initial retention of duplicate genes are not well understood. A family of genes called Hox genes have been implicated in the evolution of body plan features. However previous studies on Hox gene expression during rostrum and fin development in fish have not taken this into account. This project will examine various aspects of the molecular evolution and functional divergence of duplicated Hox genes in paddlefish. The proposed work is significant because it identifies genetic pathways associated with the evolution of novel structures, via maintenance of duplicate genes in the most diverse vertebrate group, ray-finned fishes. This work has important and broad impacts because it contributes to the training of underrepresented minority and female students at San Francisco State University, a primarily undergraduate institution that serves large numbers of minority students. In addition, the results of this research will be infused into the undergraduate curricula at San Francisco State.