“…Both EM and GP approaches managed to, respectively, learn probabilities of Stochastic Context-Free Grammars (SCFG) for RNA structure prediction [15,16,17] and derive non-probabilistic CFGs for non-biological problems [18]. Successful applications of evolutionary algorithms to SCFG [19,20,21] include our earlier research on SCFGs for protein binding sites [22]. Since, unlike EM techniques, GA-based grammar inference allows introducing pressure towards more compact grammars (see Methods) and is less dependent on initial estimates of rule parameters [20], we choose this approach for learning grammar rules.…”