Over the last few years, molecular biologist Ashley Teufel has begun to notice an emerging trend in high-profile papers on protein evolution. In particular, researchers are reporting on entrenchment, a phenomenon in which a single event can have a widespread effect on an entire system. For a protein, a genetic mutation that occurs at one point in time may help determine the way the molecule evolves later.

Teufel, an SFI Complexity Postdoctoral Fellow, realized that entrenched systems occur elsewhere. “This can’t just be a weird thing that happens to proteins,” she says. “There must be an overarching, larger concept.”

Entrenchment speaks broadly to the idea that the history of a system determines its current behaviors. The idea is similar to hysteresis, a phenomenon in which a change in one part of the system can change its behavior later in time (often observed in magnetic systems). Entrenchment is also similar to the concept of evolutionary contingency, which suggests that random accidents shape the future course of a living system. The first plant seeds to land on a new volcanic island, for example, may determine its future vegetation.

Evidence for entrenchment can be found in biology, ecology, computer science, and elsewhere. People’s ideas and feelings can even become entrenched over time. “What are the requirements that all these systems share?” asks evolutionary ecologist Luis Zaman,
a Collegiate Fellow at the University of Michigan. To find out, Teufel and Zaman have organized a working group titled “The Point of No Return,” at SFI in October. Invitees include researchers from disparate fields, including ecology, network theory, atmospheric science, and even sociology. Their goal is to identify the underlying properties driving entrenchment, and find ways to infer, predict or even control it.

The diversity of interests in the working group will fuel new insights and collaborations about how entrenchment works, says Teufel. “One of the strengths is having so many people from different fields collaborate on this to build some larger framework,” she says.