Research Techniques Made Simple: CRISPR Genetic Screens.

CRISPR and Cas proteins, often referred to as CRISPR/Cas, are the components of a bacterial genome editing system that can be used to perturb genes in cells and tissues. A classic application is to use CRISPR/Cas to generate genetic loss-of-function. When performed at large scale and combined with deep sequencing techniques, CRISPR-based perturbations can be performed in a high throughput setting to screen many candidate genomic elements for their roles in a phenotype of interest. Here, we discuss major considerations in the design, execution, and analysis of CRISPR screens. We focus on CRISPR knockout screens but also review adaptations to the CRISPR/Cas system that highlight the versatility of the system to make other types of experimental genetic changes as well. We also discuss examples of CRISPR genetic screens in investigative dermatology and how they may be used to answer key scientific questions in the field.