Does your DNA impact your lifespan?
Do we know which parts of our DNA relate to our ageing, and how much of an effect it has? Georgia Mills spoke to Joao Pedro Magalhaes from Liverpool University.
Jaoa - You can actually quantify the impact of genetics, the heritability of longevity, and the heritability of human longevity is about 25%. That means that 25% is genetic. Now that is not much. Having said that, one thing we also know is that heritability of human longevity increases with age. So what it means is that long-lived individuals like centenarians have a much greater genetic component to their longevity than for the rest of us.
Joao - I became interested in ageing when I was a child. I was quite young and I first became aware of my own mortality and the fact that everyone ages and dies, and that scared me. That scared me a lot - the fact that my parents were going to age and die and ultimately, not how well I took care of my health, I took care of myself, I would age and die.
This was before the internet so I wasn’t even aware that you could study ageing, but I was aware of the biomedical research. I knew we had medicines that could cure diseases that we couldn’t cure decades ago. I thought I would be the first one to study ageing and not just would I study ageing, but I would develop a cure for it, so from a very early age I decided that this was the road I would embark on - understanding ageing and ultimately curing ageing.
Georgia - You say curing ageing, does that mean that you consider ageing to be a disease?
Joao - That’s a very good question, but I think it’s mostly an issue of semantics whether it’s classified as a disease or not. Aging as a process is very detrimental and it is indirectly the reason what more than two-thirds of people in the world today die of. So from that perspective, ageing is a detrimental process that causes tremendous suffering, diseases, and death, and from that perspective, it is something that we should try to intervene on and try to fight.
Georgia - So now he has a lab devoted to understanding the ageing process, which includes looking at the genetics involved.
Joao - What we’re trying to do is we’re trying to identify which genes are involved in this exceptional human longevity and hopefully, if we can identify genes, then we may be able to discover drugs of small molecules that mimic the effects of longevity genes for the rest of us allowing us all to live longer, healthier lives.
Georgia - Okay. How are you trying to pinpoint these super long-life genes?
Joao - We have projects using human datasets like the UK Biobank and the Framingham Heart Study to try to identify genes associated with longevity and age-related diseases. We also have a collaboration with scientists in the US to study supercentenarians. These are individuals that live over 110 years, and so we’re trying to identify genes in these individuals that are associated with their exceptional longevity.
Georgia - Have you found any candidates yet?
Joao - There are a few candidates but there’s nothing definitive. I mentioned earlier that we know a lot about genetic manipulations of ageing in animal models, so there’s been huge advances in genetic regulation of ageing in animals. We know of hundreds of genes that can regulate ageing in animals.
Having said that, there’s a big gap in our knowledge about the genetic basis of human longevity. And although there are a few genes associated with human longevity, this explains very little of the variation in human longevity, of the heritability of human longevity. So the answer is no, we don’t understand yet why some people live over 100 years or 110 years - that still remains to be discovered.