Bacteria form colonies on many natural surfaces, from tree bark to our own teeth. Now, a team of evolutionary biologists in Switzerland has identified genetic mutations that enable some bacterial colonies to expand rapidly. The findings, recently reported in PLoS Biology, suggest that mutations in just a few key genes can have widespread impacts on gene expression as bacteria replicate and move into new territory. “It’s really creative work,” says evolutionary biologist William Ratcliff, Associate Professor and Co-Director of the Interdisciplinary Ph.D. in Quantitative Biosciences in the School of Biological Sciences, who was not involved in the study. “Understanding the way that [bacteria] might evolve in nature, the complex life cycles that they possess, and how they respond to different kinds of environments can be really hard.”