The Harvard Medical School (HMS) announced Tuesday the creation of its first new department in more than 20 years—in systems biology.

Currently at the forefront of biomedical research, systems biology is the study of functional units at the cellular level. Harvard is one of the first universities nationwide to form such a department, and with an expected size of 20 faculty, it will be one of the HMS’ largest.

Marc W. Kirschner, who currently heads the school’s cell biology department, has been tapped to lead the new department, which will seek to apply its findings to the development of clinical treatments.

“As we understand more about the tiniest pieces that we are made of, it becomes increasingly clear that we do not understand how they work together as systems,” Kirschner said in a press release. “We need to build on the foundation of molecular biology to construct an understanding of the architecture of the cell and how cells cooperate across organ systems, with a predictive mode of physiology as the ultimate goal.”

The department will have an interdisciplinary focus, recruiting experts from mathematical areas as well as more conventional biomedical fields.

The new effort will seek to establish stronger ties between HMS and other parts of the University, including affiliated teaching hospitals and the Faculty of Arts and Sciences. It also aims to connect with other Boston-area biomedical institutions like MIT’s Computational and Systems Biology initiative.

HMS Dean Joseph B. Martin said in the release that the school needed to pursue systems biology to stay on the cutting edge of medical research.

“It is worrying that we do not understand how most drugs work,” he said. “In evaluating this challenge, we reached the conclusion that the scale of the effort required demands a new department...We hope this will become a model for other departments in medical schools and colleges across the country.”

—Staff writer Stephen M. Marks can be reached at marks@fas.harvard.edu.