The genetic difference between humans and chimpanzees is small -- less than 2% -- yet the two species are undeniably distinct at the organism level. In a classic paper, Mary-Claire King and Allan Wilson argued that differences between humans and chimpanzees are predominantly due to differences in gene regulation, rather than gene identity (Science, 1975). In this talk, I will survey mechanisms of gene regulation and some mathematical models for describing these systems, highlighting why we should care about their dynamics.