Dimensions: Collaborative Research: Integrating phylogenetic, genetic, and functional approaches to dissect the role of toxin tolerance in shaping Drosophila biodiversity

长期以来，科学家和公众一直着迷于对环境的不同寻常的适应。关于形态结构（如形状、颜色、大小）的进化，人们进行了大量的研究。然而，人们对新的生化适应的进化以及这些适应对生物多样性的影响知之甚少。特别令人感兴趣的是，如果这些特征对拥有它们的个体来说代价高昂，它们是如何产生的。本研究探讨生物化学适应的进化及其形成的遗传和生态机制。这项研究探讨了昆虫（果蝇）对它们食用的蘑菇中强效毒素的耐受性。通过研究毒素耐受性的机制以及这种独特的适应性如何在该模型系统中保持，研究将增强对新性状如何出现和塑造生物多样性的一般理解。该项目还包括旨在提高公众科学素养和对生物多样性的熟悉程度的活动，方法是培训从中学到本科阶段的教师和学生（特别是来自代表性不足的少数民族的教师和学生），并制作与蘑菇有关的昆虫物种的照片识别指南。来自某些果蝇群体的果蝇以有毒和无毒蘑菇为食，并且可以耐受高剂量的强效环肽蘑菇毒素，这种毒素对大多数其他多细胞生物都是致命的。本研究验证了以下假设：1)对这些有毒环肽的耐受性进化了多次；2)不同物种耐受性的遗传机制不尽相同；3)容忍的生理成本与获得低竞争资源的收益之间的权衡维持了容忍。利用代谢组学和转录组学分析，在系统发育框架内对不同蝇种的耐受性机制及其进化进行了表征。为了评估毒素耐受性变异的遗传基础，研究人员正在进行人工选择实验和基因组测序。最后，观察和竞争实验被用来确定选择压力如何在自然种群中维持毒素耐受性。总之，本研究将对一种昂贵的新型生化适应及其对生物多样性的影响进行深入的进化、生态和生理评估。

Unusual adaptations to the environment have long fascinated scientists and the public. There has been much research to understand the evolution of morphological structures (e.g., shape, color, size). However, far less is known about the evolution of novel biochemical adaptations and the impact of these adaptations on the biodiversity of the organisms in which they appear. Of particular interest is how these traits arise if they are costly to the individuals who harbor them. This research investigates the evolution of biochemical adaptations and the genetic and ecological mechanisms that shape them. The research explores the tolerance of insects (fruit flies) to potent toxins in mushrooms that they consume. By investigating the mechanism of toxin tolerance and how this unique adaptation is maintained in this model system, the research will enhance the general understanding of how novel traits emerge and shape biodiversity. This project also includes activities designed to increase public scientific literacy and familiarity with biodiversity by training teachers and students, from middle school to the undergraduate level (particularly from underrepresented minorities), and generating photographic identification guides for insect species associated with mushrooms.Flies from some groups of Drosophila feed on both toxic and non-toxic mushrooms, and can tolerate high doses of potent cyclopeptide mushroom toxins that are deadly to most other multi-cellular organisms. This research tests hypotheses that predict that: 1) tolerance to these toxic cyclopeptides evolved multiple times; 2) the genetic mechanism of tolerance is not the same in all species; and 3) trade-offs between the physiological costs of tolerance and the benefits of access to a low-competition resource maintain tolerance. The mechanisms of tolerance and their evolution within different fly species are being characterized using metabolomic and transcriptomic analyses that are analyzed in a phylogenetic framework. To assess the genetic basis of variation in toxin tolerance, the researchers are performing artificial selection experiments and genome sequencing. Finally, observational and competition experiments are being used to identify how selective pressures maintain toxin tolerance in natural populations. In sum, this research will provide an in-depth evolutionary, ecological, and physiological assessment of a costly and novel biochemical adaptation, and its impact on biodiversity.