Our susceptibility to disease may be determined less by genetics and more by age as we get older, a new study has shown.

Researchers set out to examine the role that genetics, aging and the environment have on which genes get ‘turned on’ or ‘turned off’, which plays a role in how prone we are to disease as we age.

The team from the University of California found that differences in DNA play less of a role as we age and become more susceptible to diseases such as diabetes and cancer.

Peter Sudmant, UC Berkeley assistant professor of integrative biology, said: “How do your genetics – what you got from your sperm donor and your egg donor and your evolutionary history – influence who you are, your phenotype, such as your height, your weight, whether or not you have heart disease?

“There’s been a huge amount of work done in human genetics to understand how genes are turned on and off by human genetic variation. Our project came about by asking, ‘How is that influenced by an individual’s age?’ And the first result we found was that your genetics actually matter less the older you get.”

It means that when we are younger, our individual genetics can predict the extent to which genes ramp up or down – which impacts on our body’s workings – but this becomes less useful in older age.

Assistant professor Sudmant said the research could influence future studies, saying that research into diseases associated with older age should concentrate less on genetic variants.

He said: “Almost all human common diseases are diseases of aging: Alzheimer’s, cancers, heart disease, diabetes. All of these diseases increase their prevalence with age.

“Massive amounts of public resources have gone into identifying genetic variants that predispose you to these diseases. What our study is showing is that, well, actually, as you get older, genes kind of matter less for your gene expression. And so, perhaps, we need to be mindful of that when we’re trying to identify the causes of these diseases of aging.”

He added: “Across all the tissues in your body, genetics matters about the same amount. It doesn’t seem like it plays more of a role in one tissue or another tissue. But aging is vastly different between different tissues. In your blood, colon, arteries, oesophagus, fat tissue, age plays a much stronger role than your genetics in driving your gene expression patterns.”

Read the full study in Nature Communications.

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