 Approaches to the design of genome @-@ wide RNAi libraries can require more sophistication than the design of a single siRNA for a defined set of experimental conditions . Artificial neural networks are frequently used to design siRNA libraries and to predict their likely efficiency at gene knockdown . Mass genomic screening is widely seen as a promising method for genome annotation and has triggered the development of high @-@ throughput screening methods based on microarrays . However , the utility of these screens and the ability of techniques developed on model organisms to generalize to even closely related species has been questioned , for example from C. elegans to related parasitic nematodes . 
