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

对环境的不同寻常的适应长期以来一直让科学家和公众着迷。已经有很多研究来了解形态结构(例如，形状、颜色、大小)的进化。然而，关于新的生化适应的进化以及这些适应对出现这些适应的生物的生物多样性的影响，人们所知的要少得多。尤其令人感兴趣的是，如果这些特征对持有这些特征的个人来说代价高昂，它们是如何产生的。这项研究调查了生物化学适应的进化以及塑造它们的遗传和生态机制。这项研究探索了昆虫(果蝇)对它们所食用的蘑菇中的强烈毒素的耐受性。通过研究毒素耐受性的机制以及这种独特的适应是如何在这个模式系统中保持的，这项研究将加强对新特征如何出现和塑造生物多样性的总体理解。该项目还包括旨在提高公众科学素养和熟悉生物多样性的活动，方法是培训教师和学生，从中学到本科(特别是来自代表性不足的少数民族)，并为与蘑菇相关的昆虫物种制作照片识别指南。一些果蝇群体的苍蝇以有毒和无毒的蘑菇为食，可以耐受高剂量的环肽蘑菇毒素，这种毒素对大多数其他多细胞生物都是致命的。这项研究测试了一些假设，这些假设预测：1)对这些有毒环肽的耐受性经历了多次进化；2)耐受性的遗传机制在所有物种中并不相同；3)在耐受性的生理成本和获得低竞争资源的好处之间进行权衡。不同种类苍蝇的耐受机制及其进化正在利用代谢学和转录组分析进行表征，这些分析是在系统发育框架内分析的。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，观察性和竞争性实验正被用来确定选择压力如何在自然种群中维持毒素耐受性。总而言之，这项研究将对一种代价高昂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.