The genetic consequences of phenotypic loss: Transcriptomic and genome-wide analyses of pigmentation regression in cavefish.

进化变化既包括特征的增加，也包括特征的丧失。随着时间的推移，人们对这些特征的增加给予了很大的关注，但对特征的丧失却知之甚少。洞穴动物，如盲目的墨西哥洞穴鱼，有力地说明了这一现象，因为它们完全没有眼睛和色素。这项研究应用尖端的遗传工具来理解为什么特征在自然界中消失，并将平衡我们对进化如何塑造和塑造生物体对其环境的理解，从而产生自然界中发现的巨大多样性。该项目包括让公众与这种非凡的生物接触的外联活动。通过与当地学校和辛辛那提动物园的合作，格罗斯实验室将向学生和更广泛的社区介绍这种有趣的动物。此外，该研究项目将提供高中、本科生、研究生和博士后水平的培训和研究机会。此外，该项目将继续通过合作和科学会议促进与国际Astianax研究界的互动。因此，这项工作将对美国公众以及国际科学界产生积极的社会影响。该项目旨在揭示进化表型缺失背后的精确基因变化。并行的转录和基因组方法将评估基因改变(编码水平与表达水平)在一个强大的洞穴模型系统中所涉及的色素丢失，墨西哥冬虫夏草。这种淡水鱼有两种不同的形态，一种是“祖先”的表面形态，另一种是多种“衍生”的洞穴形态。一些洞穴种群是从一个较老的种群进化而来的，而另一些洞穴种群则是从一个较年轻的地表祖先种群进化而来的。这些自然复制实验使我们能够研究基因变化如何受到不同影响的影响，例如自洞穴环境殖民以来所经过的时间量。最近可用的遗传和基因组资源现在可以对已知和未知的色素沉着基因进行高分辨率研究，用于结构、表达和功能分析。这个项目将揭示多效性和独立洞穴种群的年龄如何影响伴随着特征丧失的遗传变化。最终，这项工作将有助于澄清我们对导致自然界退化的进化机制(选择与漂移)的理解。

Evolutionary change involves both the addition and loss of traits. Much attention has been paid to those traits that are added over time, but far less is known regarding the loss of traits. Cave-dwelling animals, such as the blind Mexican cavefish, powerfully illustrate this phenomenon since they completely lack eyes and pigmentation. This study applies cutting-edge genetic tools to understand why traits are lost in nature, and will balance our understanding of how evolution shapes and molds organisms to their environment, yielding the enormous diversity found in nature. This project includes outreach activities to engage the public with this remarkable creature. Through partnerships with local schools and the Cincinnati Zoo, the Gross lab will introduce both students and the broader community to this intriguing animal. Additionally, this research project will provide training and research opportunities at the high school, undergraduate, graduate and post-doctoral levels. Further, this project will continue to facilitate interactions with the international Astyanax research community through collaborations and scientific meetings. This work will therefore have positive societal impacts for the American public as well as the international scientific community.This project aims to uncover precise genetic changes underlying evolutionary phenotypic loss. Parallel transcriptomic and genomic approaches will evaluate genetic alterations (coding versus expression levels) implicated in pigmentation loss in a powerful cave model system, Astyanax mexicanus. This freshwater fish harbors two distinct morphotypes, an "ancestral" surface- and multiple "derived" cave-dwelling forms. Some cave populations descended from an 'older' stock, and some descended from a 'younger' stock of surface-dwelling ancestors. These natural replicate experiments allow us to investigate how genetic changes are impacted by diverse influences, such as the amount of time that has passed since the colonization of a cave environment. Recently available genetic and genomic resources now enable high-resolution studies of both known and unknown pigmentation genes for structural, expression and functional analyses. This project will inform how pleiotropy and the age of independent cave populations influence the genetic changes accompanying trait loss. Ultimately, this work will help clarify our understanding of the evolutionary mechanisms (selection versus drift) leading to regression in the natural world.