Geographic variation and comparative gene expression: Nature's gift to resolve the connection between the daily clock and the seasonal timer

已知的生物世界由两个强大的计时机制组成。一种是生物钟，它组织最基本的新陈代谢活动，使动植物在日常生活中得以生存。另一种机制是光周期计时器，负责组织包括繁殖、迁徙和冬眠在内的季节性活动。这两种计时机制中的任何一种不一致都是致命的。然而，对于昆虫这种地球上最丰富、最多样、在某些情况下也是最危险的动物，人们对生物钟和光周期计时器之间的联系及其整合知之甚少。这项研究将使用猪笼式植物蚊子Wyemyia smithii揭示这两种生物计时机制之间的进化遗传联系，这是唯一适合这项研究的。丝光霉菌生活在一个强烈的季节性梯度中，既包括温和的海平面气候，也包括严酷的山区气候，所有这些都发生在北卡罗来纳州的种群中。因此，黑脉金线虫在季节节律上表现出很大的变化，同时在所有海拔都表现出典型的昼夜行为。利用五个成熟的生物钟基因，我们将确定这些基因中的哪一个(如果有的话)控制着斯密微藻的季节性计时器。这些实验将代表着对生物钟基因节律表达的首次测试，以及对基于基因的光周期机制的严格、真实世界实验的测试。这些研究人员对光周期定时器的进化遗传学和生理学的研究首次证明，最近的快速气候变化正在推动动物的遗传变化。随着气候继续变暖，越来越多的热带疾病，包括登革热、西尼罗河病毒和疟疾，由热带和亚热带的昆虫携带，正在并将继续入侵美国和世界其他温带地区。识别主要生物计时机制之间联系的潜在基因将为靶向、缓解和阻断这些入侵提供强有力的工具。该实验室将继续参与各种媒体制作、研讨会和与非专业人士社区的接触。W.E.Bradshaw和C.M.Holzapfel正在与美国农业部合作，使用我们的下一代基因组方法来确定人类和牲畜疾病的蚊子媒介的遗传关系。这项研究的资金将使这些研究人员能够继续他们的本科生研究培训的长期传统。

The known biological world is organized by two powerful timing mechanisms. One, the circadian clock, organizes the most basic metabolic events that allow plants and animals to survive on a daily basis. The other mechanism, the photoperiodic timer, organizes seasonal events including reproduction, migration and hibernation. Discordance in either of these two timing mechanisms is lethal. Yet, the connections between and the integration of the circadian clock and the photoperiodic timer are poorly understood in insects, the most abundant, diverse and, in some cases, most dangerous animals on Earth. This research will reveal the evolutionary genetic connection between these two biological timing mechanisms using the pitcher-plant mosquito, Wyeomyia smithii, which is uniquely suited to this study. Wyeomyia smithii lives in a strong seasonal gradient that includes both a mild sea-level climate and a harsh mountain climate, all in populations located in North Carolina. Hence, W. smithii shows great variation in its seasonal timing while at the same time expresses typical circadian behavior at all elevations. Using five well-established circadian clock genes, we will determine which, if any, of these genes control the seasonal timer in W. smithii. These experiments will represent the first test of the rhythmic expression of the circadian clock genes, and of the genetically based photoperiodic mechanism in a rigorous, real-world experiment. The research on the evolutionary genetics and physiology of the photoperiodic timer by these researchers was the first demonstration that recent rapid climate change is driving genetic change in animals. As the climate continues to warm, increasing numbers of tropical diseases, including dengue fever, West Nile virus and malaria, carried by insects in the tropics and subtropics, are invading and will continue to invade the United States and other temperate regions of the world. Identifying the genes underlying the connections between the major biological timing mechanisms will provide a powerful tool for targeting, mitigating and interrupting these invasions. This lab will continue to participate in a wide variety of media productions, workshops, and outreach to the lay community. W. E. Bradshaw and C. M. Holzapfel are collaborating with the US Department of Agriculture to determine genetic relationships of mosquito vectors of human and livestock diseases using our next-generation genomic approaches. Funding of this research will enable these investigators to continue their long tradition of undergraduate research training.