What influences gene regulation in primates? The authors of this article employed a multi-species array within and between humans, chimpanzees, and macaques to estimate variation in liver, kidney, and heart tissue. They discovered a significant overlap across tissues of genes whose regulation evolved under stabilizing selection. Additionally, they found a correlation between selection on gene regulation and constraints at the protein sequence level, which suggests that adaptation through changes in evolutionarily constrained genes can occur by altering their regulatory patterns. Finally, there was evidence of directional selection between human and chimpanzee metabolic pathways, supporting the idea that human pathways have been remodeled in a way that is indicative of the life-style and dietary shift between humans and non-human primates.