Recent progress in genome engineering techniques in the silkworm, B ombyx mori

Rapid advances in genome engineering tools, such as zinc finger nucleases ( ZFN s), transcription activator‐like effector nucleases ( TALEN s), and the clustered regularly interspaced palindromic repeats/ CRISPR ‐associated ( CRISPR /Cas) system, have enabled efficient gene knockout experiments in a wide variety of organisms. Here, we review the recent progress in targeted gene disruption techniques in the silkworm, B ombyx mori . Although efficiency of targeted mutagenesis was very low in an early experiment using ZFN s, recent studies have shown that TALEN s can induce highly efficient mutagenesis of desired target genes in B ombyx . Notably, mutation frequencies induced by TALEN s can reach more than 50% of G 0 gametes. Thus, TALEN s can now be used as a standard tool for gene targeting studies, even when mutant phenotypes are unknown. We also propose guidelines for experimental design and strategy for knockout experiments in B ombyx . Genome editing technologies will greatly increase the usefulness of B ombyx as a model for lepidopteran insects, the major agricultural pests, and lead to sophisticated breeding of B ombyx for use in sericulture and biotechnology.