DISSERTATION RESEARCH: Genomic basis of desert adaptation in rodents

这项拟议的研究重点是三种啮齿动物种群对极端环境--沙漠生态系统的干旱--的全基因组适应。长期以来，了解使有机体能够适应环境的特征的进化史一直是进化生物学的中心目标。该项目将为最近的医学、农业和学术研究做出贡献，这些研究一直在揭示导致复杂适应特征的基因，并确定这些基因的突变对小鼠和包括人类在内的其他哺乳动物的影响。一个特别重要的问题是，“遗传工具箱”的范围有多大：对于一个常见的进化问题，比如在极端环境中茁壮成长，有多少在进化上可行的解决方案？这个项目可能会进一步加深我们对分子水平上的趋同和进化的重复性的理解。此外，研究人员将与来自代表性不足群体的本科生进行研究，并就这一项目提供公共和K12推广。超高效肾脏通常与沙漠啮齿动物有关，这些啮齿动物很少或根本不喝免费水。这项研究探索了这一特征的三个独立进化起源的遗传基础。将对三对物种的转录本进行测序，一对适应荒漠，一对适应温带，序列和表达数据将进行比较，以回答：1)在温带分类群中未见的荒漠分类群中是否存在氨基酸水平的收敛？2)部分或全部荒漠分类群中是否存在相同的基因被选择？3)在沙漠分类群中是否存在温带分类群中未见的收敛基因表达模式？这项研究的结果将为生物体适应环境的方式以及基因组如何进化提供重要的见解。

The proposed study focuses on genome-wide adaptation to an extreme environment, the aridity of desert ecosystems, across three rodent lineages. Understanding the evolutionary history of traits that allow organisms to adapt to their environments has long been a central goal of evolutionary biology. The project will contribute to recent medical, agricultural, and academic research that has been uncovering the genes responsible for complex adaptive traits and determining the effect mutations in these genes have on mice and other mammals, including humans. An especially important question is what is the extent of the "genetic toolbox": how many evolutionarily viable solutions are there to a common evolutionary problem, like thriving in an extreme environment? This project potentially will further our understanding of convergence at the molecular level and the repeatability of evolution. In addition, the investigators will engage in research with undergraduates from underrepresented groups and provide public and K12 outreach on this project.Ultra-efficient kidneys are often associated with desert rodents who drink little to no free water. This study explores the genetic basis of three independent evolutionary origins of this trait. Transcriptomes will be sequenced for three pairs of species, one desert adapted and one temperate adapted, and sequence and expression data will be compared to answer: 1) is there convergence at the amino acid level in desert taxa not seen in the temperate taxa? 2) Are the same genes under selection in some or all of desert taxa? 3) Are there convergent gene expression patterns in the desert taxa not seen in the temperate taxa? The results from this research will provide essential insight into the way organisms adapt to their environment and how genomes evolve.