National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China. Electronic address: shaocw@ysfri.ac.cn.
BGI-Qingdao, BGI-Shenzhen, Qingdao, Shandong 266555, China; BGI-Shenzhen, Shenzhen, Guangdong 518083, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China.
BGI-Qingdao, BGI-Shenzhen, Qingdao, Shandong 266555, China; Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark.
Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australian National Fish Collection, National Research Collections Australia, Hobart, TAS 7000, Australia; Australian Antarctic Division, Channel Highway, Kingston, TAS 7050, Australia.
Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China.
Department of Biology, University of Padova, Padova 35121, Italy.
BGI-Shenzhen, Shenzhen, Guangdong 518083, China; BGI-Beijing, Beijing 102601, China; State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China; State Agricultural Biotechnology Centre, Centre for Crop and Food Innovation, Murdoch University, Murdoch, WA 6150, Australia.
Australian Antarctic Division, Channel Highway, Kingston, TAS 7050, Australia.
School of Molecular and Life Sciences, Curtin University, Perth, WA 6009, Australia.
BGI-Shenzhen, Shenzhen, Guangdong 518083, China; State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
BGI-Shenzhen, Shenzhen, Guangdong 518083, China.
Nextomics Biosciences Institute, Wuhan, Hubei 430073, China.
BGI-Shenzhen, Shenzhen, Guangdong 518083, China; China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China.
Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China.
National Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Key Lab of Sustainable Development of Polar Fisheries, Ministry of Agriculture and Rural Affairs, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China.
Joint Laboratory for Translational Medicine Research, Liaocheng People's Hospital, Liaocheng, Shandong 252000, China.
Agricultural Genomics Institute, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China.
BGI-Shenzhen, Shenzhen, Guangdong 518083, China; Villum Centre for Biodiversity Genomics, Section for Ecology and Evolution, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark.
BGI-Shenzhen, Shenzhen, Guangdong 518083, China; James D. Watson Institute of Genome Science, Hangzhou 310058, China.
Section Polar Biological Oceanography, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany; Institute for Chemistry and Biology of the Marine Environment, Carlvon Ossietzky University of Oldenburg, 26111 Oldenburg, Germany; Helmholtz Institute for Functional Marine Biodiversity (HIFMB), University of Oldenburg, 26129 Oldenburg, Germany. Electronic address: bettina.meyer@awi.de.
BGI-Qingdao, BGI-Shenzhen, Qingdao, Shandong 266555, China; BGI-Shenzhen, Shenzhen, Guangdong 518083, China; Agricultural Genomics Institute, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong 518120, China; Lars Bolund Institute of Regenerative Medicine, Qingdao-Europe Advanced Institute for Life Sciences, BGI-Qingdao, BGI-Shenzhen 518120, China. Electronic address: fanguangyi@genomics.cn.
Antarctic krill (Euphausia superba) is Earth's most abundant wild animal, and its enormous biomass is vital to the Southern Ocean ecosystem. Here, we report a 48.01-Gb chromosome-level Antarctic krill genome, whose large genome size appears to have resulted from inter-genic transposable element expansions. Our assembly reveals the molecular architecture of the Antarctic krill circadian clock and uncovers expanded gene families associated with molting and energy metabolism, providing insights into adaptations to the cold and highly seasonal Antarctic environment. Population-level genome re-sequencing from four geographical sites around the Antarctic continent reveals no clear population structure but highlights natural selection associated with environmental variables. An apparent drastic reduction in krill population size 10 mya and a subsequent rebound 100 thousand years ago coincides with climate change events. Our findings uncover the genomic basis of Antarctic krill adaptations to the Southern Ocean and provide valuable resources for future Antarctic research.
Keywords: Antarctic krill (Euphausia superba); chromosome-level genome; circadian clock; environmental adaptation; giant genome size; population demography; population differentiation; repeat expansions