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研究的重要内容。到目前为止发现的所有活着的物种中，超过一半是昆虫，这使得昆虫纲成为地球上最多样化的纲，也可以说是自然史上最成功的动物之一。飞行蛋白是一种肌肉蛋白质，已知在果蝇黑腹果蝇的飞行中是必不可少的。这些研究将把系统发育分析与生化技术结合起来，以检测果蝇谱系中flightin的进化速度(目标1)，并研究flightin在昆虫和甲壳类动物中的系统发育分布和组织表达(目标2)。第一个目标是验证这一假设，即flightin处于双重进化限制(纯化和正向选择)下，以实现保守的肌肉生理功能和快速进化的行为相关功能。这一假说将通过利用果蝇的系统发育来分析flightin的进化、其多重磷酸化的倾向以及飞行肌肉的生物力学特性来验证。第二个目标是验证一个关键假设，即飞行蛋白在飞行肌肉中的分配与晚石炭世(~290 Mya)广泛的昆虫辐射有关。这一假说将通过调查从全甲纲到甲壳纲越来越深的节点来检验这一假设，通过RNA、蛋白质和免疫细胞学分析来检测flightin的表达。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，并将为综合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和为研究界生产生物试剂方面。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，并使来自代表性不足的社区和弱势背景的学生和研究人员具有包容性。这项研究产生的知识将被用于高级本科生和研究生的专题课程，并为更广泛的科学界审查文章和书籍章节。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议的期刊上。

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.