Observed versus expected compositional classes of potentials types I to VI.

<p>Compositional classes correspond to set of sequences with a given fraction of and monomers. A given compositional class contains 18- monomers type . Expected number of sequences per compositional class are estimated by sampling, for a given potential , random sequences from genotype space. Error bars represent one standard deviation from the mean. Colors code each potential type according to <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003946#pcbi-1003946-g003" target="_blank">Fig. 3</a> and <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003946#pcbi-1003946-t001" target="_blank">Table 1</a>.