All mammals are genetically closer to their fathers than their mothers, according to research by scientists at the University of North Carolina School of Medicine.
Specifically, the research shows that although we inherit equal amounts of genetic mutations from our parents – the mutations that make us who we are and not some other person – we actually “use” more of the DNA that we inherit from our dads.
The research, published in the journal Nature Genetics, has wide implications for the study of human disease, the authors say.
For instance, in many mouse models created for the study of gene expression related to disease, researchers typically don’t take into account whether specific genetic expression originates from mothers or fathers. But the UNC research shows that inheriting a mutation has different consequences in mammals, depending on whether the genetic variant is inherited from the mother or father.
“This is an exceptional new research finding that opens the door to an entirely new area of exploration in human genetics,” said Fernando Pardo-Manuel de Villena, PhD, professor of genetics and senior author of the paper. “We’ve known that there are 95 genes that are subject to this parent-of-origin effect. They’re called imprinted genes, and they can play roles in diseases, depending on whether the genetic mutation came from the father or the mother. Now we’ve found that in addition to them, there are thousands of other genes that have a novel parent-of-origin effect.”
For the study, Pardo-Manuel de Villena’s team selected three genetically diverse inbred strains of mice that were descended from a subspecies that evolved on different continents. These mice were bred to create nine different types of hybrid offspring in which each strain was used as both father and mother. When the mice reached adulthood, the researchers measured gene expression in four different kinds of tissue, including RNA sequencing in the brain. They then quantified how much gene expression was derived from the mother and the father for every single gene in the genome.
“We found that the vast majority of genes – about 80% – possessed variants that altered gene expression,” Crowley said. “And this was when we discovered a new, genome-wide expression imbalance in favor of the dad in several hundred genes. This imbalance resulted in offspring whose brain gene expression was significantly more like their father’s.”