Life is an emergent property. Individual molecules are not alive, and molecules only start to become alive when present in sufficient numbers and appropriate organization to build a cell. Understanding how life works must, necessarily, require conceptual and experimental ways to study complex interactions of many components. For decades, molecular biology has pursued a reductionist agenda in which the individual molecules involved in particular processes were identified, purified, and studied in isolation. This approach has transformed our understanding of the living world at scales ranging from enzymes to organs. However, we remain limited in our ability to understand how the molecular components work together as a system to produce life in all its variety. Systems biology aims to understand the emergent properties of living systems by combining tools from biology with approaches derived from physical and computational sciences. It is thus a quantitative discipline, yet one whose ultimate purpose is to understand actual living systems, including cells, embryos, and tissues.


As a world-leading center of fundamental biomedical research, UCSF provides an outstanding venue to pursue the study of systems-level thinking in the context of real biology. Our faculty have long played a leading role in developing molecular and high-throughput “omics” approaches to biology, giving our program a focus on the biology itself. It is possible to study systems biology questions from a purely physics or mathematical viewpoint, and such a viewpoint is clearly very important. Systems biology at UCSF focuses on the biology first, with the view of bringing in quantitative methods to answer long-standing biological questions. Such an approach, which focuses on biological questions, presents an excellent opportunity not only for students with biological backgrounds to extend their training into more quantitative directions, but also for students from non-biological backgrounds to gain true expertise in cutting-edge biological research. The fact that UCSF is a medical center also creates unprecedented opportunities to learn about systems biological approaches in the context of medicine and human disease. Precision medicine has emerged as a translational version of systems biology, and UCSF is a leading center in this important new field.

About CBS

Complex Biological Systems (CBS) is an optional curriculum emphasis designed to train PhD students in the understanding and engineering of complex biological systems from the molecular and cellular levels to the entire organism. It is offered within the Biophysics Graduate Program (BP) and the Bioinformatics (BI) pathway of the Biological and Medical Informatics Graduate Program (BMI) at the University of California, San Francisco (UCSF).

A designated emphasis is an area of specialization, such as a new method of inquiry, important field of application, or focus that is interdisciplinary. The designated emphasis can exist within one PhD graduate program or more than one program. Completion of the requirements for both the designated emphasis and the affiliated PhD graduate program will result in a notation of the designated emphasis on the doctoral diploma and the student transcript.

CBS departs significantly from traditional curricula. Students within this emphasis develop novel approaches to solving critical sociology and language problems associated with training scientists to be simultaneously conversant in the languages of biology, mathematics, physics, and engineering.

UCSF has recruited 10 new faculty members to expand expertise in critical quantitative areas and build an entirely new curriculum focused on the observation, modeling, manipulation, and design of complex biological systems. This entire curriculum is implemented within the context of our already strong programs in mainstream biology, allowing our students to immerse themselves in the mysteries of life.

Interested students must declare a Designated Emphasis prior to submitting the application for orals by filling out a Change of Degree Objective form (PDF, 1 page).

Co-directors Wallace Marshall and Orion Weiner
Manager Rebecca Dawson, MS


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