Abstract
A key objective of the research in the postgenomic era is to decipher the functions of the mammalian genome, which has remained largely enigmatic despite intensive efforts in the functional genomics field over the past two decades. To attack this problem, we have combined the CRISPR-Cas and Cre-Lox technologies to develop iMAP (inducible Mosaic Animal for Perturbation), a transformative tool for rapidly unraveling mammalian genome function in situ. Furthermore, we have used iMAP to rapidly construct a "Perturb-Atlas" profiling the functions of 90 protein-coding genes across 39 tissues in mice, which has offered rich insights into gene functions difficult to readily obtain using conventional mouse gene-targeting models. In this research highlight, we offer a brief primer on the iMAP technology, outlining its mechanism, strengths and limitations, and pointing out future directions of research in the area.