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、种类最多的陆生动物，但很少有昆虫能够在南极洲恶劣的气候中生存。遗传学证据表明，南极昆虫以及其他陆地节肢动物在更新世和更早的反复冰川事件中一直存在。因此，这些物种是理想的测试案例建模陆地南极洲的地理和不断变化的环境的进化反应。从生理学和遗传学的角度来看，比利时按蚊可能是南极陆地节肢动物中研究得最好的一种。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，缺乏密切相关物种的信息阻碍了我们确定允许在南极洲生存的精确进化机制的能力。在这项提案中，我们与来自美国，英国，法国和智利的科学家建立了国际合作，以扩大南极和亚南极蠓的生理和基因组研究。除了B。Anaeritica，我们的项目重点是Eretmoptera murphyi，一种已经入侵南极海洋的亚南极特有种，Halirytus magellanicus，一种严格的麦哲伦亚南极特有种，在火地岛，和B。albipes，一种在印度洋克罗泽岛发现的亚南极物种。这四个物种密切相关，跨越从亚南极到南极栖息地的环境梯度。我们的中心假设是，共同的机制驱动人口水平的适应当地的环境条件和宏观进化的变化，允许少数昆虫容忍南极气候。我们的具体目标是：1）通过比较生理学和转录组学表征保守的和物种特异性的极端环境适应，2）南极和亚南极蠓的比较基因组学，以确定南极适应的宏观进化特征，和3）利用种群基因组学研究多样化和位置适应的模式。我们更广泛的影响包括部署教育专业人员与我们的研究团队，以协调推广和继续我们的伙伴关系，与肯塔基州非营利组织专注于K-12干编程。

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.