Marc Wallace Kirschner (born February 28, 1945) is an American cell biologist and biochemist and the founding chair of the Department of Systems Biology at Harvard Medical School. He is known for major discoveries in cell and developmental biology related to the dynamics and function of the cytoskeleton, the regulation of the cell cycle, and the process of signaling in embryos, as well as the evolution of the vertebrate body plan. He is a leader in applying mathematical approaches to biology. He is the John Franklin Enders University Professor at Harvard University. In 2021 he was elected to the American Philosophical Society. Education and early life Kirschner was born in Chicago, Illinois, on February 28, 1945. He graduated from Northwestern University with a B.A. in chemistry in 1966. He received a Graduate Research Fellowship from the National Science Foundation in 1966 and earned a doctorate in biochemistry from the University of California, Berkeley in 1971. Career and research He held postdoctoral positions at UC Berkeley and at the University of Oxford in England. He became assistant professor at Princeton University in 1972. In 1978 he was made professor at the University of California, San Francisco. In 1993, he moved to Harvard Medical School, where he served as the chair of the new Department of Cell Biology for a decade. He became the founding chair of the HMS Department of Systems Biology in 2003. He was named the John Franklin Enders University Professor in 2009. In 2018, he was succeeded as Chair of the Department of Systems Biology by Galit Lahav. Kirschner studies how cells divide, how they generate their shape, how they control their size, and how embryos develop. In his eclectic lab, developmental work on the frog coexists with biochemical work on mechanism of ubiquitination, cytoskeleton assembly or signal transduction. At Princeton, his early work on microtubules established their unusual molecular assembly from tubulin proteins and identified the first microtubule-stabilizing protein tau, later shown to be a major component of the neurofibrillary tangles in Alzheimer's disease. In studies at UC San Francisco of the frog embryo as a model system of cell development, Kirschner identified the first inducer of embryonic differentiation, fibroblast growth factor (FGF), an early finding in the field of signal transduction. Kirschner's lab is also known for uncovering basic mechanisms of the cell cycle in eukaryotic cells. Working in Xenopus (frog) egg extracts, Kirschner and Andrew