Circadian Clock Control of Seasonal Migration

地球上的生命受到日出和日落时间的每日和季节变化的影响。为了适应这种有节奏的环境，动物、植物和微生物进化出了昼夜节律的生物钟，这种生物钟在24小时的基础上协调日常的生理和行为节奏。虽然生物钟在驱动日常生物节律中的作用是众所周知的，但它们在由于日长变化而引起的季节性反应中的作用仍不清楚。这项拟议的研究旨在了解大脑中的动物生物钟如何调节行为和生理上的季节性节奏。该项目的目的是确定在东北美洲帝王蝶(Danaus Plexippus)标志性的长距离迁徙中，大脑时钟调节季节性节律的分子机制。这些研究将解决时间生物学中的一个基本问题，并将促进我们对光周期反应和迁徙行为背后的分子机制的理解。这可能会对濒危迁徙物种的保护以及了解它们对气候变化的适应潜力产生更广泛的影响。通过这个项目，研究生和本科生将在生物钟研究和分子遗传学方面得到指导。将与当地小学和高中开展外联活动，向学生介绍公民科学，方法是参与生成关于君主迁徙模式的数据，并通过君主标记方案和创建新的君主中转站恢复其栖息地。这项拟议研究的首要目标是揭示帝王蝶远距离迁徙中钟控季节性节律背后的分子机制。由于在非模式物种(仓鼠、绵羊、鸟类)中缺乏表现出强光周期反应的基因组和遗传工具，以及在遗传易驯化的动物(苍蝇、小鼠)中缺乏强光周期反应，对动物的季节性节律和光周期反应由昼夜节律调节的分子机制的基本理解受到了阻碍。该项目将利用君主体内强大的分子、基因组和遗传工具，(I)研究生物钟和时钟基因在光周期诱导迁徙行为和生理开关中的作用，(Ii)识别潜在的迁徙开关的时钟输出基因，以及(Iii)在体内干扰候选基因，以确定它们对迁徙行为和生理的影响。这些实验将对昆虫光周期反应的分子基础和迁徙行为背后的遗传程序产生前所未有的见解。

Life on earth is subjected to daily and seasonal variations in the timing of sunrise and sunset. To adapt to this rhythmic environment, animals, plants and microbes have evolved circadian clocks that orchestrate daily rhythms of physiology and behavior on a 24-hour basis. Although the role of circadian clocks in driving daily biological rhythms is relatively well known, their role in seasonal responses due to changes in day-length remain unclear. The proposed research aims to understand how animal circadian clocks in the brain regulate seasonal rhythms in behavior and physiology. The objective of this project is to determine the molecular mechanisms through which brain clocks regulate seasonal rhythms in the iconic long-distance migration of the North Eastern American monarch butterfly (Danaus plexippus). The studies will address a fundamental question in chronobiology and will advance our understanding of the molecular mechanisms underlying photoperiodic responses and migratory behavior. This could have broader implications for the conservation of endangered migratory species, and for understanding their adaptive potential to climate change. Through this project, graduate and undergraduate students will be mentored in biological clocks research and molecular genetics. Outreach activities will be conducted with local grade and high schools to introduce students to citizen science by participating in the generation of data on monarch migration patterns and the restoration of their habitat through monarch tagging programs and the creation of new Monarch Waystations. The overarching goal of the proposed research is to uncover the molecular mechanisms underlying clock-controlled seasonal rhythms in long-distance migration of the monarch butterfly. A fundamental understanding of the molecular mechanisms by which seasonal rhythms and photoperiodic responses in animals are regulated by the circadian clock has been hampered by the lack of genomic and genetic tools in non-model species (hamster, sheep, bird) that display robust photoperiodic responses, and the lack of robust photoperiodic responses in genetically tractable animals (fly, mouse). This project will take advantage of powerful molecular, genomic and genetic tools available in the monarch to (i) examine the role of circadian clocks and clock genes in the photoperiodic induction of the migratory behavioral and physiological switch, (ii), identify clock-output genes underlying the migratory switch, and (iii) disrupt candidate genes in vivo to define their impact on migratory behavior and physiology. These experiments will yield unprecedented insight into the molecular bases of insect photoperiodic responses and the genetic program underlying migratory behavior.