Figure 3.

Gene acquisitions and losses. The method described here (see Figure 1) only identifies losses of genes (in genome A) that have been conserved in the two other lineages considered (genomes B and C; in green). If recent acquisitions (in black) are deleted shortly after their integration in the genome, what we observe is a high number of acquisitions compared with losses. This, rather than an increase in genome size, may explain the results presented in Figure 2.