Astrobiologist Betül Kaçar spends much of her time looking for signs of life in other worlds. Some of this is done in the more expected way—analyzing telescope data for biological signatures in the atmospheres of distant, giant exoplanets. But these days, she’s more focused on smaller-scale evidence of how life thrived in environments very different from today’s Earth. She finds it surprisingly close to home, in ancient DNA maintained within present-day earthly microorganisms.
In this video from The Well, Kaçar talks about why this ancient DNA holds a record of how life persisted in the hostile environment of Earth’s deep past. “Evolution keeps a record of biology solving problems,” she says. “So when you study organisms that have been around for a long time…ultimately you are going to be studying their survival strategies.”
In Kaçar’s lab at the University of Wisconsin–Madison, her team uses synthetic biology techniques to re-activate sections of ancient DNA and place microbes in high-CO2 environments closer to what their ancestors encountered 3 billion years ago. After coaxing the microbes to behave as they might have in the deep past, the team can then add stressors—from excess heat to nutrient scarcity—to see how the ancient DNA aids the organisms’ responses and evolution, in order to learn whether some of life’s old genetic tricks might have future uses. This could involve re-engineering and repurposing enzymes and metabolic processes to create crops that deliver nitrogen more effectively.
“Now we are in the process of engineering plants with DNA that belongs to a planet that once was,” Kaçar says, “but may not be that different compared to what we are headed towards.”
In order to detect life on other planets, we can expand the range of what we look for based not only on what exists on Earth now, but ancient life that thrived under different planetary conditions billions of years ago.
This post draws upon a series of videos produced by The Well, a publication and video channel produced by the John Templeton Foundation and BigThink.
Nate Barksdale writes about the intersection of science, history, philosophy, faith, and popular culture. He was editor of the magazine re:generation quarterly and is a frequent contributor to History.com.
