Research Team

Nigel Grimsley

Observatoire Océanologique de Banyuls, Biologie Intégrative des Organismes Marins (BIOM), CNRS UMR7232, UPMC Paris6, France

Complete genome analyses of six species of the smallest eukaryotic cells known (Piganeau et al., 2011b) has revealed that we do not yet know the true extent of species' diversity in these algae, because the resolution of commonly used barcoding genes is insufficient (Grimsley et al., 2010; Piganeau et al., 2011a). Giant viruses, whose genomes we have shown to carry a largely uncharacterized reservoir of biological functionalities (Moreau et al., 2010), outnumber these algal cells in the natural environment and cause chronic infection and lysis. Host resistance and viral virulence are thus in a race for life or death that forces evolution at the base of the food web (Thomas et al., 2011).

In the context of Tara Oceans, our Genomics of Phytoplankton group at the Arago marine research laboratory on the Mediterranean coast is developing two main areas of research in collaboration with the Tara consortium: (1) description of viral and host species' diversities in the Mamiellophyceaean algae using Next Generation Sequencing with existing and new marker genes to identify novel groups of species and (2) population genomics by single amplified genome analyses of individual algal cells from within algal blooms to (i) define intraspecific levels of variation and population sizes and (ii) identify the genomic targets of adaptive natural evolution in natural populations.

Relevant publications

  1. Grimsley, N., Pequin, B., Bachy, C., Moreau, H., and Piganeau, G. (2010). Cryptic Sex in the Smallest Eukaryotic Marine Green Alga. Molecular Biology and Evolution 27, 47–54.
  2. Moreau, H., Piganeau, G., Desdevises, Y., Cooke, R., Derelle, E., and Grimsley, N. (2010). Marine prasinovirus genomes show low evolutionary divergence and acquisition of protein metabolism genes by horizontal gene transfer. J. Virol. 84, 12555–12563.
  3. Piganeau, G., Eyre-Walker, A., Grimsley, N., and Moreau, H. (2011a). How and Why DNA Barcodes Underestimate the Diversity of Microbial Eukaryotes. PLoS ONE 6, e16342.
  4. Piganeau, G., Grimsley, N., and Moreau, H. (2011b). Genome diversity in the smallest marine photosynthetic eukaryotes. Research in Microbiology 162, 570–577.
  5. Thomas, R., Grimsley, N., Escande, M., Subirana, L., Derelle, E., and Moreau, H. (2011). Acquisition and maintenance of resistance to viruses in eukaryotic phytoplankton populations. Environmental Microbiology 13, 1412–1420.

The scientific activities of the Tara Oceans expedition, led by EMBL senior scientist Eric Karsenti, present an unprecedented effort that resulted in 35,000 samples containing millions of small organism collected in more than 210 ocean stations, chosen for their climatic significance or biodiversity.