"Are Devoted Fathers Born That Way?"... The Brain Gene That Divides Paternal Care

High Agouti expression leads to aggression, low expression to caregiving
Social environment flips the parenting behavior switch

Among male mammals, fewer than 5% actively care for their offspring. However, a new study has found that the qualifications for being such a "devoted father" may not be an innate temperament, but can change depending on the expression of specific genes in the brain and the social environment.

Image to help readers understand the article. Pixabay

On the 18th (local time), a research team at Princeton University in the United States reported in a paper published in the international journal Nature that they had identified how genes in the brain regulate paternal behavior, based on experiments with the African striped mouse (Rhabdomys pumilio).

In nature, it is extremely rare for male mammals to directly care for their young, occurring in fewer than 5% of species. The African striped mouse is an exception, showing a clear behavioral spectrum ranging from males that carefully nurture their offspring to those that attack them. The research team focused on the fact that this difference originates in the brain’s medial preoptic area (MPOA). The more active the paternal behavior in a male, the higher the neural activity observed in this region.

'Agouti' gene suppresses paternal care... a parenting switch in the brain

The key was the Agouti gene operating in this region. Previously, it was known as a gene related to fur color and obesity, but this study confirmed that it also plays a role in suppressing paternal behavior.

In the MPOA of males that actively cared for their young, Agouti expression levels were low, whereas in males that neglected or attacked their offspring, expression levels were high. When the research team artificially increased Agouti expression, even previously nurturing males became indifferent or aggressive.

This Agouti expression varied depending on the social environment. When males were housed alone, Agouti expression decreased and caregiving behavior increased. In contrast, when multiple males were reared competitively in a confined space, Agouti expression rose and paternal behavior declined.

Researchers: "Environment adjusts survival-parenting balance"... further research needed for humans

Postdoctoral researcher Forrest Rogers, who led the study, explained, "Even males with no experience of pregnancy or childbirth can show caregiving behavior if the brain environment changes," adding that "the Agouti gene acts as a switch that suppresses parenting behavior."

Co-corresponding author Professor Ricardo Mallarino analyzed, "Individuals adjust the balance between survival and parenting in response to external environmental factors such as population density and competition for food."

The research team noted that humans also possess the Agouti gene and an MPOA region, but it has not yet been confirmed whether the same mechanism operates. Assistant Professor Katrin Pe?a said, "Parenting is a highly complex trait, and you cannot create good parents with a single pill," but added, "This provides clues to understanding how the environment affects brain function and caregiving behavior."