Mammals are genetically more like their fathers, according to a new research which has wide implications for the study of human disease, especially when using mammalian research models.
Although we inherit equal amounts of genetic mutations from our parents, we actually "use" more of the DNA that we inherit from our fathers, said researchers at University of North Carolina (UNC) Health Care.
The research shows that inheriting a mutation has different consequences in mammals, depending on whether the genetic variant is inherited from the mother or father.
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.
"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," said Fernando Pardo-Manuel de Villena, professor of genetics and senior author of the paper.
"Now we've found that in addition to them, there are thousands of other genes that have a novel parent-of-origin effect," de Villena said.
These genetic mutations that are handed down from parents show up in many common but complex diseases that involve many genes, such as type-2 diabetes, heart disease, schizophrenia, obesity, and cancers.
Studying them in genetically diverse mouse models that take parent-of-origin into account will give scientists more precise insights into the underlying causes of disease and the creation of therapeutics or other interventions.
For the study, de Villena's team, including first author James Crowley, assistant professor of genetics, 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 per cent - possessed variants that altered gene expression," Crowley said.
"And this was when we discovered a new, genome-wide expression imbalance in favour of the dad in several hundred genes. This imbalance resulted in offspring whose brain gene expression was significantly more like their father's," Crowley said.
The study is published in the journal Nature Genetics.
