Theoretical Physicist is at Home Among Microbiologists

Christoph Adami is a theoretical physicist who finds himself at home in microbiology.

Christoph Adami has a PhD in theoretical physics, yet he is the newest member of the faculty in the Department of Microbiology and Molecular Genetics.

While this non-traditional partnership may seem odd at first glance, it has potential to take evolutionary biology research into many new areas.

Adami first came to MSU last year while on sabbatical from California and as part of BEACON – the National Science Foundation’s Science and Technology Center headquartered at MSU. The center studies evolution in action and involves many faculty from the microbiology department.

His time away from his faculty position in California was only meant to last a year. Yet, Adami has decided to join MSU as a full-time professor in microbiology where he can work alongside the biologists, computer scientists, and engineers in BEACON.

Adami first became interested in evolution during his post-doctoral studies when the director of a nuclear research facility gave him a paper on evolution inside of a computer. This stirred his passion of physics and evolution.

According to Adami, evolution can be viewed as the evolution of information. In organisms, information is encoded as genes. The tools of physics, mathematics and computer simulations are well-suited for studying information evolution.

Adami uses computational and theoretical methods of looking at evolution. He designed the AVIDA software which simulates an environment inside a computer where populations of computer programs can live and evolve.

“Simulations are the theory of today,” Adami says. “You really cannot do theoretical biology using equations anymore as the systems are too complex. Simulations are an extension of equations and they go where equations cannot.”

One of Adami’s current simulations is about cooperation and altruism. He is examining why cells help other cells when evolutionary theory suggests that every cell should look out for itself. He is studying colicin-producing bacteria to understand this behavior since the bacteria live in colonies. When non-related bacteria colonize too much of the surrounding area, the colicin-producing bacteria explode and clear the area by spraying the colicin toxin. The only bacteria which survive are kin containing a colicin resistant gene.

Adami and his group are investigating what the colicin-producing bacteria gain through this process. The fitness of the kin group is maximized when the unrelated bacteria are destroyed, but the colicin-producing bacterium is dead. Adami and his team realized the missing factor for understanding cooperation was communication.

“It is analogous to reputation in humans,” Adami notes. “We are more willing to help those who have a good reputation for helping others.”

Once communication is introduced to the simulation, cooperation is born. Cells use chemical signals to communicate their past behavior in cooperation transactions. Cooperation then becomes an evolutionary advantage. Computational testing supports this hypothesis, but it has not been tested with live cells.

“To test these things requires sophisticated experiments and you have to find the right people to do them,” Adami says. “When I first arrived here and people were talking about what they’re doing, I kept thinking, ‘Yes, that’s what I need.’ This is where I need to be.”

To test the cooperation hypothesis, Adami and his team have enlisted Ben Kerr from the University of Washington. Kerr is working with colicin-producing bacteria and will be testing Adami’s predictions in a living environment.

“Directly connecting a physicist with biologists opens up a whole new realm of possibilities,” says Walt Esselman, chair of the department. “Our faculty are excited about the potential and our students are benefiting from the new opportunities this creates for research and learning.”

So how does Adami feel about being a physicist in a department filled with biological scientists? “I feel like a kid in a candy store,” he says.

Written by Mike Steger and Angela Hobson. Reprinted from the Department of Microbiology & Molecular Genetics Alumni Newsletter, September 2011.