Research Starter Grant

进化生物学中一个重要的突出问题是，在基因水平和表型水平（即，如体型等可见特征）上，进化的可重复性如何。换句话说，如果我们能让进化时钟倒转，一次又一次地观察这个过程，每次进化都会导致同样的解决方案来应对适应性挑战吗？埃斯蒂斯博士将利用土壤线虫——秀丽隐杆线虫来解决这些问题。先前的研究表明，这些线虫种群携带许多有害的基因突变（因此表现出适应性降低），可以通过获得补偿原始有害突变的二次突变迅速恢复适应性。埃斯蒂斯博士将确定这些潜在的“补偿性”突变的身份，它们是否发生在与原始突变相同的遗传途径中，以及复制种群是否采取相同的进化途径来恢复适应性（即，种群是否倾向于获得相同的补偿性突变？）实验进化，传统的遗传分析和微阵列技术允许测量单个基因的表达水平将被用来解决上述问题。这项工作将通过培训本科生研究人员，包括未来的科学教育工作者，将研究和教育结合起来。波特兰州立大学通过与美国印第安人一起参与科学和工程以及教育公平项目，正在寻求本科生研究人员参与这一项目和其他项目。此外，国家进化综合中心和进化目录正在通过广告寻找有才华的少数民族研究生。埃斯蒂斯博士将担任一名教学硕士研究生、一名本科生研究员和一名博士后助理的联合顾问，协助这个项目和其他项目。

A major outstanding question in evolutionary biology asks how repeatable evolution is at the level of genes and at the level of phenotype (i.e., visible characteristics such as body size). In other words, if we could rewind the evolutionary clock and view the process again and again, would evolution lead to the same solutions to adaptive challenges each time? Dr. Estes will address these questions using the soil nematode, Caenorhabditis elegans. Previous work has shown that populations of these nematodes harboring many deleterious genetic mutations (and thus exhibiting reduced fitness) can rapidly recover fitness via the acquisition of secondary mutations that compensate for the original deleterious mutations. Dr. Estes will determine the identity of these underlying "compensatory" mutations, whether they occur in the same genetic pathways as the original mutations, and whether replicate populations take the same evolutionary route to fitness recovery (i.e., do populations tend to acquire the same compensatory mutations?). Experimental evolution, traditional genetic analyses, and microarray technology allowing measurement of the level of expression of individual genes will be employed to address the above questions. This work will integrate research and education through training of undergraduate researchers, including future science educators. Through involvement with American Indians in Science and Engineering and the Educational Equity Programs at Portland State University, undergraduate researchers are being sought to participate in this and other projects. Also, talented minority graduate students are being sought through advertising with the National Evolutionary Synthesis Center and the Evolution Directory. Dr. Estes will serve as co-advisor for a Master's of Science in Teaching student, an undergraduate researcher, and one postdoctoral associate assisting with this and other projects.