On the cover: Spontaneous mutations in the germline are a significant factor influencing genetic risk for autism spectrum disorders (ASDs). Using whole-genome sequencing of autism families, Michaelson et al. (pp. 1431–1442) determine the intrinsic characteristics of the genome that influence regional mutation rates and quantify the effect of paternal age on global mutation rate. Mutation rates vary widely throughout the genome, and regional hypermutation emerges as a factor determining the contribution of individual genes to risk for ASD and other disorders in the population. Cover artwork by Evgeny Buryat Onutchin.