Cover image

The laboratory mouse is one of the primary model organisms in human biology and genetics research. The generation and phenotypic analysis of mutations in the mouse has been key for functional studies, and this process has made great strides with targeted mutagenesis in embryonic stem cells and CRISPR–Cas gene editing in preimplantation embryos. Strains harboring mutations in many genes are now available or can be easily produced. In this issue, Papaioannou and Behringer introduce an overall strategy for generating a mutation in mice and systematically analyzing the phenotype (doi:10.1101/pdb.over107955). Cover art: Two Mice in Council (1830–1849), Katsushika Hokusai (1760–1849), Library of Congress Prints and Photographs Division Washington, D.C. 20540, USA, http://hdl.loc.gov/loc.pnp/jpd.02816.