NSFGEO-NERC: Mechanisms of Adaptation to Terrestrial Antarctica through Comparative Physiology and Genomics of Antarctic and sub-Antarctic Insects

昆虫是地球上数量最多、种类最多的陆地动物，但很少有昆虫能够在南极洲不适宜居住的气候中生存。遗传证据表明，南极昆虫以及其他陆生节肢动物在更新世及更早的反复冰川事件中一直存在。因此，这些物种是模拟南极洲陆地生物地理和对环境变化的进化反应的理想测试案例。从生理学和遗传学的角度来看，南极洲的侏儒或许是研究得最好的南极陆生节肢动物。这个物种是最南端的自由生活的昆虫，我们最近参与了这个物种的基因组和转录组的测序。然而，缺乏来自密切相关物种的信息，阻碍了我们查明允许在南极洲生存的确切进化机制的能力。在这项建议中，我们与来自美国、英国、法国和智利的科学家建立了一个国际合作，以扩大南极和亚南极吸虫的生理和基因组研究。除了南极洲以外，我们的项目还专注于入侵海洋南极的亚南极特有种Eretmoptera Murphy、火地岛特有的严格麦哲伦亚南极物种Halirytus Magellanicus和印度洋克罗泽特岛上发现的亚南极物种B.albipe。这四个物种密切相关，跨越了从亚南极到南极栖息地的环境梯度。我们的中心假设是，共同的机制既推动了种群水平对当地环境条件的适应，也推动了允许少数昆虫耐受南极气候的宏观进化变化。我们的具体目标是1)通过比较生理学和转录组学来表征保守的和物种特有的对极端环境的适应，2)南极和亚南极媒介的比较基因组学以确定南极适应的宏观进化特征，以及3)利用种群基因组学研究多样性和区位适应的模式。我们更广泛的影响包括部署一名教育专业人员与我们的研究团队一起协调外展，并继续我们与肯塔基州一家专注于K-12 STEM计划的非营利性组织的合作伙伴关系

Insects are the most abundant and diverse terrestrial animals on the planet, yet few are capable of surviving in Antarctica's inhospitable climate. Genetic evidence indicates that Antarctic insects, as well as other terrestrial arthropods, have persisted throughout the repeated glaciation events of the Pleistocene and earlier. Thus, these species are ideal test cases for modeling the biogeography of terrestrial Antarctica and evolutionary responses to changing environments. The midge Belgica antarctica is perhaps the best studied Antarctic terrestrial arthropod in terms of physiology and genetics. This species is the southernmost free-living insect, and we recently participated in sequencing the genome and transcriptome of this species. However, a lack of information from closely related species has hindered our ability to pinpoint the precise evolutionary mechanisms that permit survival in Antarctica. In this proposal, we establish an international collaboration with scientists from the US, UK, France, and Chile to expand physiological and genomic research of Antarctic and sub-Antarctic midges. In addition to B. antarctica, our project focuses on Eretmoptera murphyi, a sub-Antarctic endemic that has invaded the maritime Antarctic, Halirytus magellanicus, a strictly Magellanic sub-Antarctic species endemic to Tierra del Fuego, and B. albipes, a sub-Antarctic species found on Crozet Island in the Indian Ocean. These four species are closely related and span an environmental gradient from sub-Antarctic to Antarctic habitats. Our central hypothesis is that shared mechanisms drive both population-level adaptation to local environmental conditions and macroevolutionary changes that permit a select few insects to tolerate Antarctic climates. Our Specific Aims are 1) Characterize conserved and species-specific adaptations to extreme environments through comparative physiology and transcriptomics, 2) Comparative genomics of Antarctic and sub-Antarctic midges to identify macroevolutionary signatures of Antarctic adaptation, and 3) Investigate patterns of diversification and location adaptation using population genomics. Our Broader Impacts include deploying an education professional with our research team to coordinate outreach and continuing our partnership with a Kentucky non-profit focused on K-12 STEM programming