Phosphorylation and fungal evolution Phosphorylation after transcription modifies the activity of proteins. To understand how phosphorylation sites have evolved, Studer et al. studied a range of fungal species (see the Perspective by Matalon et al. ). Only a few sites were apparently present in the common ancestor of all 18 species investigated. Evolutionary age appeared to predict the potential functional importance of specific conserved phosphosites. Science , this issue p. 229 ; see also p. 176