Researchers may soon be able to predict how long a person will live based on their genetics. This could result from the discovery by a University of Glasgow team in Scotland showing that telomere length on the ends of DNA in their genes in early-life predicts life spans.
Professor Pat Monaghan, research team leader said, “Each time a cell divides, some DNA can be lost at the end of the chromosome,” Monaghan said. “The cap is worn down without affecting the integrity of the chromosome itself. But each time a cell divides, some of this protective cap is lost. Eventually, it’s eroding or fraying away until no cap is left. Then genetic structure in the cell is lost, so that cell may die or malfunction.” Once a cell is no longer able to divide or begins to deteriorate, it contributes to the decline in tissue and organ function. This increases the risk of cancer and other diseases as a person ages over time. But for individuals with longer telomeres in early life, their cells receive more protection over time. “If the telomere is longer, there’s more to wear away,” Monaghan said.
The Glasgow team on Tuesday published their findings in the American Proceedings of the National Academy of Sciences. The researchers were the first to measure telomere length in the young and then repeatedly during the rest of their natural lives. They found telomere length in early-life is strongly predictive of the individual’s subsequent lifespan.
They measured telomere lengths in small samples of blood cells taken at various ages in a group of zebra finches – small black-, white- , orange-, and gray-striped and -spotted birds – whose lifespan varied from just 210 days to almost nine years. The best predictor of longevity was the telomere length at just 25 days.
Researcher Dr. Britt Heidinger said, “while there was a lot of variation among individuals in telomere length, those birds that lived longest had the longest telomeres at every measurement point.” It is known that the variation in telomere length is partly inherited, but also varies due to variation in environmental factors such as exposure to stress.
Prof. Karen B. Avraham – a leading member of the department of human molecular genetics and biochemistry at Tel Aviv University’s Sackler Faculty of Medicine commented, “This discovery is a dramatic one, showing the strength of using model organisms to tell us about normal human health and disease. If a correlation between zebra finches and humans turns out to be relevant for telomere length and longevity, I predict it is a matter of time before we will all want to test the length of our telomeres,” she said. “The take-home message here should also be to reduce stress in our life from as early an age as possible – this may help us live longer.”
Monaghan also emphasized the importance of early-life conditions. “Our study shows the great importance of processes [occurring] early in life. We now need to know more about how early life conditions can influence the pattern of telomere loss and the relative importance of inherited and environmental factors. This is the main focus of our current research,” she said.
A study of this magnitude would be difficult to conduct on humans, since it could be a whole century before the results could be analyzed. But the findings are still significant for humans. Dr. Brit Heidenger, one of the researchers under Monaghan, said the next step in their research is to understand why some individuals have longer telomeres than others. “The interesting findings is that such an early stage in life, we have evidence that lifespan is predicted by telomere length,” Dr. Heidenger said. “Now we want to know how much is due to environmental factors or hereditary factors. We could look at what kind of parenting they receive or food they’re exposed to. If we find that environmental factors matter in terms of telomere length, it could have a very big impact.”
While the team is excited about the results of their research, Heidenger noted it is important for people not to think there is a ticking clock inside of them. “We want to be cautious about how people interpret this,” Dr. Heidenger told FoxNews.com. “Although telomeres are a strong predictor, they are still just a predictor. It isn’t like we can look at telomere length and know exactly how long an individual will live…It’s just letting you know the probability.”
“This study is important,” says María Blasco, a telomere researcher at the Spanish National Cancer Research Centre in Madrid. “It’s the first time that normal differences in telomere length have been shown to be predictive of longevity.” Blasco was not involved in the current study, but serves as chief scientific adviser for Madrid-based company Life Length, which advertises telomere length measurements as a service for determining an individual’s “biological age”.
However Monaghan said, “It is not understood why there are variations of telomere length but if you had a choice, you would want to be born with longer telomeres. If you were to test this, I don’t think anyone would want to know – it would just make you miserable. But it must be remembered that how you live has a big effect. This isn’t quite a case of nature overtaking nurture.”