Figure 6

Specificity of amino acid repeats. The degeneracy of the genetic code prompted us to determine whether amino acid repeats would provide a better picture of the frequency of repeated features in the fungal ORFeomes. For this, the repeats were quantified and displayed as shown. In the diagram, and for each species, the first line in each column from the top corresponds to cases in which the amino acid appeared isolated in ORFs. The second line corresponds to isolated pairs of identical amino acids and so on, so that, for each column, higher number of lines correspond to longer amino acid strings. As expected, amino acid repeats were biased, as indicated by the color scale used in the map, where light blue corresponds to repressed repeats and the brown color indicates preferred repeats. Yellow represents repeats whose observed and expected frequencies were similar. Amino acid repeats were amino acid specific. For example, Gln, Asp, Glu, Asn or Ser (first group on the left) formed long strings more frequently than expected (brown), while strings of Phe, Ile, and Leu were repressed in all ORFeomes (blue bars). C. albicans had the longest strings of almost all amino acids, in particular of Asn, Pro, His and Thr (highlighted in grey, top of the diagram).