Every organism responds to the world with an intricate cascade of biochemistry. There’s a source of heat here, a faint scent of food there, or the crack of a twig as something moves nearby. Each stimulus can trigger the rise of one set of molecules in an animal’s body and perhaps the fall of others. The effect ramifies, tripping feedback loops and flipping switches, until a bird leaps into the air or a bee alights on a flower. It’s a vision of biology that entranced Andreas Wagner, an evolutionary biologist at the University of Zurich, when he was still a young student.
“I thought that was much more fascinating than this idea that biology is about counting the number of things that are out there,” he said. “I realized biology could be about fundamental principles of organization in living systems.”
His career, which has included stints at the Santa Fe Institute and the Institute for Advanced Study in Berlin, has taken him from modeling the regulation of gene transcription in an embryo, where precision timing makes the difference between life and death, to asking how an organism can manage to evolve when any change in its genes could spell disaster. He has used theoretical models to probe difficult questions about what drives evolution, and he has wondered about evolutionary innovations that seem to lead nowhere — until they suddenly become the next big thing. His most recent book, Sleeping Beauties: The Mystery of Dormant Innovations in Nature and Culture (Oneworld Publications, 2023), is an exploration of this phenomenon.
Quanta spoke to Wagner over the phone recently about his new book, evolution as exploration, and the grand patterns that underlie biology. The interview has been condensed and edited for clarity.
When I first met you about 10 years ago, you were talking about the paradox of trying to evolve an organism: How can changes occur in a working genome without everything falling apart? How did you come to focus on that problem?
I remember a conversation with somebody many years ago where we were discussing why organisms are diploid — that is, why do they have two copies of their genes? I said, “Maybe because if one copy is defective due to mutation, the other one provides a backup.” And the other person said, “No, this would be too simplistic.” I didn’t find out until 20 years later that I was probably onto something there, because there’s now been a lot of work that suggests this could be one of the reasons why diploidy is abundant in nature. That was the first link to this concept of robustness: that diploidy can provide organisms with robustness to mutations.
It’s something that I rediscovered when I started working on gene regulatory networks. These model networks evolve through mutation and selection, and over time they become increasingly robust against disruptions by mutations. I became really fascinated with that.
I realized that this kind of robustness could be linked to the ability of populations to explore many, many different genotypes during evolution without losing a phenotype that’s well adapted. In doing so they could stumble on new phenotypes that they would not be able to otherwise. I’m still fascinated by this link between the ability of biological systems to withstand perturbations — for example, mutations — and their ability to explore new things.