(a) Comparison of AAC between serine phosphorylation sites and non-phosphorylation sites for seven organisms. The vertical axis denotes the log2 ratio of the averages of amino acid frequencies for phosphorylation and non-phosphorylation sites. (b) Difference in 544 physicochemical properties based on IG scores. Two-sample Logos of composition biases around serine phosphorylation sites compared to the non-phosphorylation sites for (c) Aspergillus and (d) S. pombe.