Evolutionary genomics of a cold-adapted diatom: Fragilariopsis cylindrus

Thomas Mock, Robert P. Otillar, Jan Strauss, Mark McMullan, Pirita Paajanen, Jeremy Schmutz, Asaf Salamov, Remo Sanges, Andrew Toseland, Ben J. Ward, Andrew E. Allen, Christopher L. Dupont, Stephan Frickenhaus, Florian Maumus, Alaguraj Veluchamy, Taoyang Wu, Kerrie W. Barry, Angela Falciatore, Maria I. Ferrante, Antonio E. FortunatoGernot Glöckner, Ansgar Gruber, Rachel Hipkin, Michael G. Janech, Peter G. Kroth, Florian Leese, Erika A. Lindquist, Barbara R. Lyon, Joel Martin, Christoph Mayer, Micaela Parker, Hadi Quesneville, James A. Raymond, Christiane Uhlig, Ruben E. Valas, Klaus U. Valentin, Alexandra Z. Worden, E. Virginia Armbrust, Matthew D. Clark, Chris Bowler, Beverley R. Green, Vincent Moulton, Cock Van Oosterhout, Igor V. Grigoriev

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263 Citations (Scopus)
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The Southern Ocean houses a diverse and productive community of organisms1, 2. Unicellular eukaryotic diatoms are the main primary producers in this environment, where photosynthesis is limited by low concentrations of dissolved iron and large seasonal fluctuations in light, temperature and the extent of sea ice3, 4, 5, 6, 7. How diatoms have adapted to this extreme environment is largely unknown. Here we present insights into the genome evolution of a cold-adapted diatom from the Southern Ocean, Fragilariopsis cylindrus8, 9, based on a comparison with temperate diatoms. We find that approximately 24.7 per cent of the diploid F. cylindrus genome consists of genetic loci with alleles that are highly divergent (15.1 megabases of the total genome size of 61.1 megabases). These divergent alleles were differentially expressed across environmental conditions, including darkness, low iron, freezing, elevated temperature and increased CO2. Alleles with the largest ratio of non-synonymous to synonymous nucleotide substitutions also show the most pronounced condition-dependent expression, suggesting a correlation between diversifying selection and allelic differentiation. Divergent alleles may be involved in adaptation to environmental fluctuations in the Southern Ocean.
Original languageEnglish
Pages (from-to)536–540
Number of pages5
Early online date16 Jan 2017
Publication statusPublished - 26 Jan 2017

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