There are two hair cell subtypes in the cochlea of the inner ear that develop from progenitors: inner hair cells (IHCs) and outer hair cells (OHCs). This scanning electron microscopy image (34 μM by 27 μM) was taken from a mouse with overexpression of a gene essential for IHC development. In light blue are the stereocilia of IHCs and in green are the stereocilia of IHC-like cells, which progenitors that would be OHCs develop into after overexpression of the gene. See the article by Zhenghong Bi et al. for more information on how they used this mouse model to investigate molecular and genetic mechanisms of hair cell fate determination and maturation to inform hair cell regeneration strategies. Cover image: Zhiyong Liu.