PONDERING whether a baby got mum or dad’s eyes may seem like idle speculation, but knowing which parent certain genes came from can tell you about your risk of disease. Some variants are even two-faced, boosting the risk if they come from one parent but cutting it if they come from the other.
It is already known that the same gene variant can behave differently depending on which parent it came from, due to a process called imprinting – which determines which of a parent’s genes are expressed in the child.
Now a team led by at deCODE genetics in Reykjavik, Iceland, has looked at hundreds of thousands of single-letter DNA variations to examine how imprinting affects the risk of disease. For 38,000 Icelanders, his team determined whether these variations came from the mother or father, and looked for correlations with disease.
Advertisement
The researchers identified at least five variations whose correlation with a certain disease depended on whether the gene is maternal or paternal. An earlier study that didn’t take parental influence into account found one variant on chromosome 11 raised the risk of breast cancer by 7 per cent. Stefánsson’s study shows that it in fact ups the risk by 17 per cent if inherited from the father but protects against the disease if it comes from the mother.
The team also found disease-linked variants that other studies had missed. One of these boosts a person’s risk of type 2 diabetes by 41 per cent, but only if they inherit it from the father.
Mental illness
“We are going to find more common variants underlying disease, and this is one example of that,” Stefánsson says.
By uncovering these hidden variations, researchers should be able to better explain the hard-to-find genetic components of diseases such as mental illnesses, says , an epigeneticist at Duke University in Durham, North Carolina.
“This paper brings to the forefront the real importance of genomic imprinting in disease susceptibility, which we miss a lot of the time,” he says.
Journal reference:
