SALT LAKE CITY — The amount of genetic influence moms and dads have on their kids’ behavior is not the same, according to a new study. Each parent’s genetic information affects the decisions of their sons and daughters differently, say scientists.
Most genes are passed down from one generation to the next in pairs, with one copy coming from each parent. They contain genetic information, some of which helps produce hormones and regulate feelings of stress, fear, anxiety and reward. But now scientists at the University of Utah Health reveal that genes from each parent impacts their kids’ mood and behavior in different ways.
“We’re really intrigued that there is this untapped area of biology that controls our decisions,” says Christopher Gregg, principal investigator of the study and associate professor in the university’s Department of Neurobiology, in a statement.
Gregg and his team focused on a gene dubbed dopa decarboxylase which makes an enzyme used in the production of hormones like dopamine and serotonin. To study it, the researchers genetically modified mice so that a fluorescent tag would appear blue if the enzyme was produced by genes copied from the father and red if from the mother. This way they could simply look under a microscope and see which parent’s copy of the gene was active.
Groups of neurons which only used the mother’s copy were discovered in 11 regions of the rodents’ brains. The researchers also studied their adrenal glands where dopa decarboxylase is used to produce adrenaline, the hormone which triggers the mouse’s fight or flight response to danger or stress. This time they found groups of cells relying exclusively on the gene copy inherited from their father.
A series of experiments were carried out to see which copy – from the mother or father – had more influence on the rodents behavior During these experiments the mice were free to explore while being confronted with various fears and motivations, much like in the wild.
Machine learning, a type of artificial intelligence, was used to map their complex behavioral patterns. Differences in the way mice, with mutations in either copy of the gene, foraged for food were observed by the researchers. Each parent’s gene affected their offspring differently, with mothers having more control over some of their sons’ decisions and fathers some of their daughters.
“Not everybody has the same sort of interests, outcomes, and selective effects,” says Gregg. “Daughters need to rear litters. Sons often disperse and will go to new environments.”
Switching off one parent’s copy in a select group of cells could therefore have a significant impact on their behavior.
The researchers have also found evidence that several other genes are biased towards one of the parents’ genetic copies. “I dream of this new field of decision genetics, where we systematically uncover the parental gene copies that control specific decisions and actions in particular contexts,” says Gregg. “Such studies could lead researchers to cells and neural circuits with previously unrecognized roles in behavior.”
The findings are published in the journal Cell Reports.
South West News Service writer Tom Campbell contributed to this report.