Figure 1.

Scaling laws. The number of protein-domains associated with functional categories 'translation' (green), metabolic process' (blue), and 'regulation of transcription' (red) as a function of the total number of domains in the genome for which a functional annotation is available. Each dot corresponds to a fully-sequenced microbial genome, with the total number of domains on the horizontal axis and the number of domains in a particular functional category on the vertical axis. Both axes are shown on a logarithmic scale. The straight lines show power-law fits.