The transition can be bumpy, but biologists are hiring physicists into their labs and departments in hopes of accelerating the pace of discovery.

Larry Hardesty

As cell and molecular biology become more quantitative—generating mountains of data on cellular processes, from gene expression to biochemical signaling—more physical scientists are working on biological problems. But some, in Boston and elsewhere, are going even further, switching fields altogether and getting jobs in what have traditionally been pure biology departments.

It’s a risky career move, but many physicists are lured by the prospect of engaging with real human problems—and by the greater funding available for research in the life sciences. Some are also tired of postponing experiments until the next mammoth particle accelerator gets built.

Biologists, in turn, recognize that analyzing the data they’re generating is no longer a part-time job. Many believe that bringing the tools of physics—and the physicists themselves—into their labs and departments will yield better research results sooner than working with preoccupied colleagues across campus.

“Once we have the tools for measuring the parameters of interest, be it gene expression or steps of development, the possibility opens up for the kind of analyses and hypothesis generation and testing that physicists are trained to do,” says John Coffin, a Tufts immunologist whose lab has a renegade physicist on staff.

In addition to new tools, physical scientists moving into biology bring with them expectations and ways of thinking that can clash with those of their new colleagues. But from that clash, a new synthesis is beginning to emerge.

Making the leap

Igor Rouzine, a former condensed-matter theoretician, joined Tufts’s molecular biology and microbiology department as a postdoc in Coffin’s lab and has stayed on as a research associate professor. He says he has no regrets about turning his back on a promising career in physics. “There were no deep problems that were still soluble,” he says.

As a physics postdoc at the University of California, Los Angeles, Rouzine learned that HIV researchers had started developing mathematical models of the immune system, and he began reading some of their papers in his spare time. “I immediately saw some internal deficiencies in these theories,” he says. “I thought I could do better—in a purely mathematical sense.”

So he moved to Coffin’s lab, which studies the interactions between the HIV virus and the human immune system. He began building very simple computer models of those interactions; he also enrolled in graduate biology classes and immersed himself in the immunology literature.

As his understanding of immunology increased, so did the complexity of his models. Still, they weren’t complex enough to satisfy some of his new colleagues. When Rouzine began presenting his work at biology conferences, he was “shocked at the aggressiveness” with which it was sometimes received, he says.

Culture gap

Indeed, physicists and biologists have fundamentally different ways of thinking. Biologists “tend to dismiss simple and elegant mathematical solutions because they are convinced that biology is inherently very complex,” says Franziska Michor, an evolutionary biologist at Harvard who trained in both math and molecular biology. Harvard neurobiologist David Corey, whose lab makes its own laser-optical equipment and regularly hires engineers and physicists, says that learning physics is a matter of mastering a few universally applicable concepts. In biology, however, the vital skill has always been “understanding how lots of little bits of information are linked to each other.”

But that distinction is beginning to blur. “People in charge of graduate programs and curriculum were extremely open to changing courses geared for biology students to a more quantitative approach,” says Antoine van Oijen, an assistant professor at Harvard Medical School who studies DNA replication at the single-molecule level but got his PhD in physics. “That tells me that biochemistry, molecular biology, and cell biology are very open to the idea of introducing rigorous quantitative methods into biology,” he says.

Rouzine, too, says that biologists are much more receptive to his models than they were 10 years ago. And as these barriers continue to fall, cross-disciplinary hiring will only increase, says Coffin.

But will enough physicists be willing to take the leap into biology? “The opportunity to acquire whole new fields of training and education while being paid for it,” says van Oijen, “is a pretty sweet deal.”