A new study by scientists at the University of Utah explains how mom and dad's genes shape behaviour. Each parent has a unique influence on hormones and other chemical messengers that control mood and behaviour.

The findings of the research were published in the journal Cell Reports. Parenting is not the only way moms and dads impact the behaviour of their offspring. Genes matter, too. And although most of our genes are inherited in pairs, one copy from each parent, moms and dads exert their genetic influence in different ways.

"We're intrigued that there is this untapped area of biology that controls our decisions," said Christopher Gregg, PhD, principal investigator and associate professor in the Department of Neurobiology. A clearer picture of the genetic factors that shape behaviour is a crucial step toward developing better diagnoses and treatments for psychiatric disorders, he said.

Gregg's research team reports that certain groups of cells in the brains of an experimental model rely exclusively on the mother's copy of a gene that is needed to produce essential chemical messengers in the brain called neurotransmitters. In those cells, the father's copy of the gene remains switched off. However, in a different organ, the adrenal gland, certain cells favour the father's copy of the same gene.

There, the gene is involved in producing the stress hormone, adrenaline. After identifying this unexpected switch in parental control of a single gene, Gregg's team went on to demonstrate that it had consequences for behaviour found that each parent's gene affected sons and daughters differently: certain decisions in sons were controlled by their mother's gene, whereas fathers had control over some decision-making in daughters.

Evolutionarily speaking, this form of genetic regulation may reflect different parental priorities, Gregg says. "Not everybody has the same sort of interests, outcomes, and selective effects," he explained. "Daughters need to rear litters. Sons often disperse and will go to new environments." Consequently, it may be in parents' interest to influence behaviour differently in their sons and daughters.

"The revelation that maternal and paternal alleles of the same gene along the brain-adrenal axis could have disparate, or possibly even antagonistic, phenotypic consequences on behaviour is an intriguing observation," said the paper's first author, Paul Bonthuis, PhD, an assistant professor in the Department of Comparative Biosciences at the University of Illinois at Urbana-Champaign.

"The brain-adrenal axis is a very important part of mammalian biology that controls behaviour and affects stress, mood, metabolism and decision-making," Gregg explained. He said that this finding is a first step toward understanding how a parent's genes may affect more routine behaviours and related health conditions in people, from mental illnesses and addiction to cancer and Alzheimer's disease.