Bacterial cells can “remember” brief, temporary changes to their bodies and immediate surroundings, a new Northwestern University and University of Texas-Southwestern study has found.

And, although these changes are not encoded in the cell’s genetics, the cell still passes memories of them to its offspring — for multiple generations.

Not only does this discovery challenge long-held assumptions of how the simplest organisms transmit and inherit physical traits, it also could be leveraged for new medical applications. For example, researchers could circumvent antibiotic resistance by subtly tweaking a pathogenic bacterium to render its offspring more sensitive to treatment for generations.

The study was published today (Aug. 28) in the journal Science Advances.

“A central assumption in bacterial biology is that heritable physical characteristics are determined primarily by DNA,” said Northwestern’s Adilson Motter, the study’s senior author. “But, from the perspective of complex systems, we know that information also can be stored at the level of the network of regulatory relationships among genes. We wanted to explore whether there are characteristics transmitted from parents to offspring that are not encoded in DNA, but rather in the regulatory network itself. We found that temporary changes to gene regulation imprint lasting changes within the network that are passed on to the offspring. In other words, the echoes of changes affecting their parents persist in the regulatory network while the DNA remains unchanged.”

Motter is the Charles E. and Emma H. Morrison Professor of Physics at Northwestern’s Weinberg College of Arts and Sciences and director of the Center for Network Dynamics. The study’s co-first authors are postdoctoral fellow Thomas Wytock and graduate student Yi Zhao, who are both members of Motter’s laboratory. The study also involves a collaboration with Kimberly Reynolds, a systems biologist at the University of Texas Southwestern Medical Center.