Argonaute-interacting WG/GW proteins are characterized by the presence of repeated sequence motifs containing glycine (G) and tryptophan (W). The motifs seem to be remarkably adaptive to amino acid substitutions and their sequences show non-contiguity. Our previous approach to the detection of GW domains, based on scoring their gross amino acid composition, allowed annotation of several novel proteins involved in gene silencing. The accumulation of new experimental data and more advanced applications revealed some deficiency of the algorithm in prediction selectivity. Additionally, W-motifs, though critical in gene regulation, have not yet been annotated in any available online resources.