Flipping a single genetic switch can cause eager fathers to attack their offspring, at least in African striped mice, new research suggests. But the gene itself was not solely responsible for this transition from attentive to aggressive fathering; social conditions also played a role in how the male mice behaved.
The findings may reveal more about the genetic mechanisms that cause some species of mammals to act as caring fathers while others abandon their young. Active fathering is rare in mammals, with only 5% of the 6,000 mammal species that have involved dads. Because of this, scientists know far less about how maternal care works in mammals than they know about maternal care in mammals. African striped mice (Rhabdomys pumilio) are useful for studying mammalian paternal care because males display a wide range of behaviors toward pups, from huddling to keep pups warm to actively ignoring their offspring.
To determine the brain regions that mediated this behavior, the team exposed male mice to pups, then monitored their brain activity. They found that the mindful dads had greater activity in a brain region called the medial preoptic area (MPOA).
“Decades of work have shown that the MPOA functions as a hub for maternal care across mammals,” lead author and postdoc. Dr. Forrest Rogersa researcher at the Princeton Neuroscience Institute, told LiveScience in an email.
The team then dissected the brains of the mice and measured gene activity in cells from the MPOA. From this, they discovered that a gene called Agouti was more active in males that attacked pups than in males that cared for the pups.
“Agouti is better known for his roles in skin pigmentation and metabolism, so it was exciting to discover this previously unknown role in the brain for parenting behavior,” Rogers said in a statement.
To confirm that Agouti expression was responsible for the transition between attentive and aggressive behavior, the team first exposed mice to pups, then injected a virus that enhanced expression of the Agouti gene in the MPOA. When the males were again exposed to puppies, their behavior changed.
“We found that the males, when Agouti was increased, became aggressive toward pups,” Rogers told LiveScience in an email, suggesting that this gene acted as a kind of “switch” that alternated between aggressive and caring behavior in mouse fathers.
While the Agouti gene found in the MPOA may have a strong link to the change in paternal care, Rogers cautioned that this molecular switch was not the whole story.
“It certainly appears that for some striped mice, increasing Agouti expression is sufficient to induce infanticide,” he said. “However, we also found that there were other factors at play, such as today’s social housing, which could moderate this effect.”
When the researchers moved males from group housing to solitary cages, Agouti levels dropped and grooming increased, suggesting that the gene is influenced more by social context than by food availability.
Although this study may have uncovered a possible paternal genetic switch, there were important limitations. Specifically, only male African striped mice were studied. And although fathering behavior varied within the species, the researchers cautioned against translating these findings to other species.
“While we would not rule out that Agouti may function similarly in other species (human or otherwise), there is no current evidence to suggest this specific function in humans (or other mammalian species),” Rogers said in his email to Live Science.
Rogers, FD, Kim, S., Mereby, SA, Kasper, AM, Callanan, AB, Mallarino, R., & Peña, CJ (2026). Agouti integrates environmental cues to regulate paternal behavior. Nature. https://doi.org/10.1038/s41586-026-10123-4
