Evolutionary genomics of a cold-adapted diatom: Fragilariopsis cylindrus

Mock, Thomas, Otillar, Robert P., Strauss, Jan, McMullan, Mark, Paajanen, Pirita, Schmutz, Jeremy, Salamov, Asaf, Sanges, Remo, Toseland, Andrew, Ward, Ben J., Allen, Andrew E., Dupont, Christopher L., Frickenhaus, Stephan, Maumus, Florian, Veluchamy, Alaguraj, Wu, Taoyang, Barry, Kerrie W., Falciatore, Angela, Ferrante, Maria I., Fortunato, Antonio E., Glöckner, Gernot, Gruber, Ansgar, Hipkin, Rachel, Janech, Michael G., Kroth, Peter G., Leese, Florian, Lindquist, Erika A., Lyon, Barbara R., Martin, Joel, Mayer, Christoph, Parker, Micaela, Quesneville, Hadi, Raymond, James A., Uhlig, Christiane, Valas, Ruben E., Valentin, Klaus U., Worden, Alexandra Z., Armbrust, E. Virginia, Clark, Matthew D., Bowler, Chris, Green, Beverley R., Moulton, Vincent, Van Oosterhout, Cock and Grigoriev, Igor V. (2017) Evolutionary genomics of a cold-adapted diatom: Fragilariopsis cylindrus. Nature, 541. 536–540. ISSN 0028-0836

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    Abstract

    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.

    Item Type: Article
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    Faculty of Science > School of Computing Sciences
    Depositing User: Pure Connector
    Date Deposited: 23 Jan 2017 21:32
    Last Modified: 17 Jan 2019 01:07
    URI: https://ueaeprints.uea.ac.uk/id/eprint/62155
    DOI: 10.1038/nature20803

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