Targeted mutagenesis: A sniper-like diversity generator in microbial engineering.

Mutations, serving as the raw materials of evolution, have been extensively utilized to increase the chances of engineering molecules or microbes with tailor-made functions. Global and targeted mutagenesis are two main methods of obtaining various mutations, distinguished by the range of action they can cover. While the former one stresses the mining of novel genetic loci within the whole genomic background, targeted mutagenesis performs in a more straightforward manner, bringing evolutionary escape and error catastrophe under control. In this review, we classify the existing techniques of targeted mutagenesis into two categories in terms of whether the diversity is generated in vitro or in vivo, and briefly introduce the mechanisms and applications of them separately. The inherent connections and development trends of the two classes are also discussed to provide an insight into the next generation evolution research.