This photomicrograph reflects the experimental power of CRISPR/Cas9 genome editing. Tbx21-Cre mice were bred to a Cas9 line with a GFP reporter and then gRNA targeting the voltage dependent potassium channel, Kv1.3, was retroorbitally delivered. The CRISPR-associated Cas9 protein is restricted to the mitral and tufted output neurons of the olfactory bulb (green) allowing the CRISPR guide RNA (red) to edit the channel from the genome in the target neurons (yellow). This confers the mouse with enhanced olfaction and resistance to diet-induced obesity. For more information, see the article by Kolling et al. (pages 5966–5990). Cover image: Louis Kolling.