Ratcliff and Yunker: 2019 Sigma Xi Faculty Best Paper Award

Collaboration between biologist and physicist leads to groundbreaking discovery

Georgia Tech has named William Ratcliff and Peter Yunker as recipients of the 2019 Sigma Xi Faculty Best Paper Award.

Ratcliff was recently promoted to associate professor in the School of Biological Sciences and a member of the Center for Microbial Dynamics and Infection. Yunker is an assistant professor in the School of Physics. Both are members of the Parker H. Petit Institute of Bioengineering and Bioscience.

The award recognizes the authors of an outstanding paper. Ratcliff and Yunker are co-principal authors of the paper “Cellular packing, mechanical stress and the evolution of multicellularity,” published in Nature Physics in 2018.

“[The paper] exemplifies the power of interdisciplinary collaboration and best reflects Georgia Tech’s institutional culture of creative and rigorous exploration.”

The paper was the first to recognize the role of mechanics in the early evolution of multicellular organisms. Ratcliff and Yunker showed “how physical stress may have significantly advanced the evolutionary path from single-cell to multicellular organisms,” according to a 2017 story about this work. “In experiments with clusters of yeast cells called snowflake yeast, forces in the clusters’ physical structures pushed the snowflakes to evolve.

“Like the first ancestors of all multicellular organisms, in this study the snowflake yeast found itself in a conundrum: As it got bigger, physical stresses tore it into smaller pieces. So, how to sustain the growth needed to evolve into a complex multicellular organism?

“In the lab, those shear forces played right into evolution’s hands, laying down a track to direct yeast evolution toward bigger, tougher snowflakes.”

The partnership has profoundly shaped the two scientists’ research programs. “The paper reflects the deep collaboration between the Yunker and Ratcliff labs,” a colleague says. “It exemplifies the power of interdisciplinary collaboration and best reflects Georgia Tech’s institutional culture of creative and rigorous exploration.”

“There are few things better than doing exciting, creative science with good friends,” Ratcliff says.

“I’m delighted to share this recognition with such a great team,” Yunker says.