With a background in traditional process control, the Doyle lab is focused on biosystems analysis and control, with an eye to both unraveling the complex regulatory circuitry that underlies biological networks, as well as reverse-engineering principles of biological control for subsequent application in engineering systems. The research group bring tools from systems engineering, including nonlinear dynamics, system identification, and control design, to unravel the complex feedback architectures in nature. The lab's work in systems biology has made important contributions towards understanding an array of diseases and biological systems, including: the unfolded protein response, type 2 diabetes, heat stroke, PTSD, and Alzheimer’s. The largest and most impactful body of the lab's work contribution in this field has centered on the rich regulatory architecture underlying circadian rhythm generation in the brains of flies and mammals. Focusing on network aspects of the clock, both at the gene regulatory level and the intercellular coupling scale, the Doyle group was the first to publish experimentally validated mathematical predications, that phenotypes at the cellular level contradict the behavior observed at the organism or tissue level. (modified from https://sleep.med.harvard.edu/people/faculty/1699/Francis+J+Doyle+III+PhD)