Molecular function distribution. Molecular function distribution for four groups of genes: N_F, A_F, N_S, and A_S (no AS gene families genes, AS gene families genes, noAS singletons, and AS singletons, respectively). Only categories having proportion larger than 1% are shown, and categories having a proportion smaller than 1% are tallied together as “others”. There is an enrichment (more than 6 times) of molecular transducer activity for N_F compared to the other three groups. The molecular transducer activity for N_F, A_F, N_S and A_S are 23.9%, 3.3%, 3.6% and 2.3% respectively.