DISSERTATION RESEARCH: Evolution of a novel phenotypes: The role of generalized enzyme function in adaptation

在细胞内有数千种复杂的生化相互作用，其中许多是由非常特定的酶介导的。复杂的生化相互作用的进化可能遵循一个循序渐进的过程，每一种酶的新精制都是通过自然选择来优化的。然而，关于这些复杂的相互作用是如何演变的，以及是什么进化力量塑造了它们，人们知之甚少。通过研究具有不同形式的生物体系统发育树中酶的结构变化，人们可以追踪一种新的生化途径的进化历史，并确定特定的功能细化发生的时间。具体地说，有可能利用当今生物化学途径的变异来推断已灭绝的祖先途径背后的DNA序列。DNA信息可以用来推断祖先的路径，从而确定它的功能，并理解进化是如何作用于它，创造出当前的路径。利用十字花科植物(包括花椰菜、卷心菜和油菜等作物)，PI将研究生物化学途径的进化，以形成一种对阻止草食动物至关重要的化学物质。这笔赠款还将支持研究生在当地小学的外展工作和对8年级女孩的指导。在这项研究期间，将加强国际合作。最后，通过这种生化途径产生的抗食草动物化合物被认为在预防癌症方面发挥了作用，因此这里描述的基础研究可能具有医学和农业重要性。

Within a cell there are thousands of complex biochemical interactions, many of which are mediated by very specific enzymes. The evolution of complex biochemical interactions could follow a stepwise process, with each new elaboration of an enzyme being optimized by natural selection. However, very little is known about how these complex interactions have evolved and what evolutionary forces shape them. By examining the changing structures of an enzyme within the context of the phylogenetic tree of the organisms that have the different forms, one can trace the evolutionary history of a novel biochemical pathway and determine when a particular functional elaboration took place. Specifically, it is possible to use the variations in the present-day biochemical pathway to infer the DNA sequence underlying the extinct ancestral pathway. The DNA information can be used to infer the ancestral pathway and thus determine its function and understand how evolution acted on it to create the current pathway. Using plants of the family Brassicaceae (which includes crops like broccoli, cabbage, and canola), the PIs will examine the evolution of the biochemical pathway for forming a chemical that is crucial to deterring herbivores. This grant will also support the graduate student's outreach work at local elementary schools and the mentoring of 8th grade girls. International collaborations will be strengthened during this research. Finally, the anti-herbivore compounds made by this biochemical pathway are thought to play a role in cancer prevention, so the basic research described here could have medical as well as agricultural importance.