Jonathan Karr joined the Column Group as a Swanson Fellow in 2023 after completing his PhD in molecular and cellular biology at UC Berkeley under Robert Tjian and Xavier Darzacq. His thesis work focused on exploring new frameworks for understanding eukaryotic gene regulation that incorporate the findings of recent dynamical studies of nuclear proteins. In collaboration with Dr. Jack Ferrie, he published a new model of enhancer–promoter communication and a treatise on the inadequacy of classical biochemical intuitions as applied to eukaryotic transcription regulation. Just before joining the Group, he published a single-molecule imaging study that demonstrates a fundamental principle of transcription coactivator function—that it depends on integrating multiple transcription factor inputs via multivalent, semi-disordered interactions. He also holds a BS/MS in biochemistry from Colorado State University, where he studied structural biology under Profs. Karolin Luger and Olve Peersen.