The core and accessory genomes of marine picocyanobacteria. (a) Number of genes distributed between the core and accessory components of each of the 11 Synechococcus and 3 Prochlorococcus genomes used in this study. The core genome common to all picocyanobacteria is indicated as green bars. The Synechococcus-specific core genome includes an additional set of genes shown as orange bars. The accessory genome is split between unique genes, indicated as white bars, and genes shared between 2-13 genomes, indicated as light grey bars. Note that when considering marine picocyanobacteria, genes shown in orange are part of the accessory genome. (b) Same as (a) but showing percentage of genes. (c) Number of unique genes relative to genome size. (d) Cumulative size of islands (red bars) and giant open reading frames (ORFs; white bars) relative to total genome size. (e) Same as (d) but showing percentage of base-pairs. (f) Cumulative length of islands versus size of Synechococcus genomes.
Dufresne et al. Genome Biology 2008 9:R90 doi:10.1186/gb-2008-9-5-r90