Molecular Phylogeny of Flightin and the Evolution of Insect Flight Muscle

昆虫飞行的起源和进化是进化生物学的一个重要研究课题。迄今为止发现的所有现存物种中有一半以上是昆虫，这使得昆虫成为地球上最多样化的物种，也可以说是自然历史上最成功的动物之一。飞行蛋白是一种肌肉蛋白，对果蝇的飞行至关重要。这些研究将结合系统发育分析和生化技术来研究果蝇谱系中飞行蛋白的进化速度（目标1），并研究昆虫和甲壳类动物中飞行蛋白的系统发育分布和组织表达（目标2）。第一个目的是测试飞行蛋白在双重进化约束（净化和积极选择）下实现保守的肌肉生理功能和快速进化的行为相关功能的假设。这一假设将通过果蝇系统发育分析飞行蛋白的进化，其多重磷酸化倾向和飞行肌肉的生物力学特性来验证。第二个目的是验证一个关键假设，即飞行肌肉的飞行蛋白与晚石炭世（~290亿年前）的广泛昆虫辐射有关。这一假设将通过调查从全代谢纲到甲壳纲的泛壳纲系统发育中越来越深的节点来检验，通过RNA、蛋白质和免疫细胞学分析来表达飞行蛋白。上述目标的实现将有助于阐明肌肉的分子生理学和细胞力学与昆虫的生态行为空气动力学和进化之间的机制联系，并将为合成最多产的陆生后生动物的宏观和微观进化趋势铺平道路。这项研究的其他更广泛的影响主要是在教育领域和为研究界生产生物试剂。这项研究将为本科生和研究生以及偶尔的高中生提供培训机会，并为来自代表性不足的社区和弱势背景的学生和研究人员提供包容性。从这项研究中产生的知识将用于高级本科和研究生专题课程，并用于更广泛的科学界的评论文章和书籍章节。结果将由本科生和研究生广泛传播，他们将在科学会议上展示他们的工作，并将他们的研究发表在同行评审的期刊上。

The origin and evolution of insect flight is of major interest in evolutionary biology. More than half of all living species identified to date are insects making Insecta the most diverse class on Earth and arguably among the most successful animals in natural history. Flightin is a muscle protein known to be essential for flight in the fruit fly, Drosophila melanogaster. These studies will combine phylogenetic analyses with biochemical techniques to examine the rate of evolution of flightin among Drosophila lineages (aim 1) and to examine the phylogenetic distribution and tissue expression of flightin across insects and crustaceans (aim 2). The goal of the first aim is to test the hypothesis that flightin is under dual evolutionary constraints (purifying and positive selection) to fulfill a conserved muscle physiological function and a rapidly evolving behavior-associated function. This hypothesis will be tested by using Drosophila phylogeny to analyze the evolution of flightin, its propensity for multiple phosphorylations, and flight muscle biomechanical properties. The goal of the second aim is to test a key hypothesis that the assignation of flightin to the flight muscles correlates with the extensive insect radiation during the late Carboniferous (~290 Mya). This hypothesis will be examined by surveying increasingly deeper nodes in Pancrustacea phylogeny, from Holometabola to Crustacea, for expression of flightin by RNA, protein, and immunocytological analyses. The achievement of the stated goals will help to elucidate the mechanistic links between molecular physiology and cellular mechanics of muscle and the ecobehavioral aerodynamics and evolution of insects, and will pave the way towards a synthesis of the macro-and microevolutionary trends in the most prolific terrestrial metazoan. Additional broader impacts of this research are primarily in the areas of education and the generation of biological reagents for the research communities. This research will provide training opportunities for undergraduate and graduate students, and occasional high school students, and inclusiveness of students and research personnel from underrepresented communities and disadvantaged backgrounds. Knowledge generated from this research will find its way to advanced undergraduate and graduate special topic courses and to review articles and book chapters intended for the broader scientific community. Results will be broadly disseminated by undergraduate and graduate students who will present their work at scientific meetings and will publish their studies in peer-reviewed journals.