Collaborative Research: The impacts of the distribution of phenotypic effects and the distribution of pleiotropic costs on the genetics of natural adaptations

基因不是单独起作用的。它们作为大型基因网络的一部分发挥作用，共同产生我们观察到的生物体特征（表型）。然而，并不是所有的基因对网络的贡献都是一样的，有些基因可能对多种性状有贡献。基因之间的这种差异表明，一些基因变化可能比其他基因变化影响更大；改变一个在几个性状中起重要作用的基因，可能比改变一个在单个性状中起相对次要作用的基因更有效果。一般来说，大的影响变化被认为对生物体是有害的。然而，当生物体面临强大的进化挑战时，例如，接触杀虫剂或药物，吃新的食物，遇到病原体，这些巨大的影响变化可能是其生存的唯一希望。本研究将通过研究具有不同程度网络相互作用的基因的表型成本，来检验关于进化适应性表型的性质和可预测性的假设。该项目还将为未被充分代表的群体的学生提供关键分子和进化概念的实践培训。这个项目测试了这样一个假设，即一些基因，比如那些在网络中处于中心位置的基因，可能是性状进化的基因“热点”。为了验证这一想法，该项目使用了描述良好的果蝇嗅觉系统作为模型遗传网络。与人类一样，苍蝇的嗅觉系统进化迅速，并与一些适应性直接相关。尖端的基因组测序、化学感觉基因进化分析和超细尺度形态分析将用于测试适应性生态变化是否可预测地与嗅觉系统中特定类型的变化相关。然后，这些预测将在嗅觉相关表型上进行测试，使用果蝇中可用的强大遗传工具。

Genes do not operate alone. They function as parts of large gene networks that work together to produce the organism traits we observe (phenotypes). However, not all genes contribute equally to a network and some genes may contribute to multiple traits. This difference among genes suggests that some genetic changes may have more impact than others; changes in a gene that has a large role in several traits presumably has more effect than changing a gene with a relatively minor role in a single trait. In general, large effect changes are thought to be bad for an organism. However, when that organism faces a strong evolutionary challenge, for example, an exposure to a pesticide or drug, eating a new food, encountering a pathogen, these large effect changes may be the only hope for its survival. This research will test hypotheses concerning the nature and predictability of evolving adaptive phenotypes by examining the phenotypic costs of genes having varying degrees of network interaction. This project will also provide hands-on training for students from underrepresented groups in key molecular and evolutionary concepts. This project tests the hypothesis that some genes, such as those that are central in networks, may be genetic 'hotspots' of trait evolution. To test this idea, this project uses the well-described fruit fly (Drosophila) olfactory system as a model genetic network. In flies, as with humans, the olfactory system evolves rapidly and is directly tied to some adaptations. Cutting edge genomic sequencing, analysis of chemosensory gene evolution, and ultrafine scale morphological analysis will be used to test whether adaptive ecological shifts are predictably associated with particular types of changes in the olfactory system. These predictions will then be tested on olfactory related phenotypes using the powerful genetic tools available in Drosophila.