Life expectancy is largely determined by genetic predisposition - which means it can be predicted based on genetic screening.
At one time, the journal Science published the results of an unusual study: having studied only 150 genetic variations (single nucleotide polymorphisms), scientists are able to predict with almost 80% accuracy who will be able to live to a ripe old age.
Researchers at Boston University have used a widely used genetic screening technique to look for genetic sequences that are found in centenarians - people aged 100 or more.
In addition to a potential way to predict who will survive to their 100th birthday, the study demonstrates the significant influence of genetic factors on life expectancy. The researchers hope that identifying genes and related molecular mechanisms that promote longevity will help delay or even prevent various age-related diseases such as heart disease, Alzheimer's and even cancer in the future.
Previous results from the world's largest research project on centenarians showed that 90% of them continue to lead a fulfilling life by the age of 93, avoiding disability-related diseases. Also interesting is the fact that centenarians, on average, have the same amount of genetic variation associated with any disease as people in the control group. This suggests that life expectancy does not depend on the absence of a genetic predisposition to disease, but on the genes that predetermine longevity.
The findings also cast doubt on the validity of genetic tests performed to calculate an individual's risk for a specific disease (such as type 2 diabetes or cancer). The results of the study should be confirmed on a larger sample, but if they correspond to the truth, then attempts to identify the risk of the disease outside the general genetic context may be considered incorrect.
By comparing the genomes of 1,055 centenarians and 1,267 people from the control group, the researchers identified 33 genetic variations out of about 30,000, which are much more common in the long-liver group. Each of these variations individually played a minor role, and scientists developed a computer model to reveal the cumulative effect of different genetic variations. Based on the list of genetic variations that were most different between the study and control groups, the scientists identified 150 of them with the highest predictive value.
This model is able to “guess” the long-liver in 77% of cases; the reason for the longevity of the remaining 23% can be both genetic factors that have not yet been taken into account, and the influence of the environment, which is not taken into account in modeling. People over the age of 108 had the largest number of isolated genetic variations.
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The researchers are very cautious in their conclusions and emphasize that the study needs to be repeated on a new sample, since the study and control groups belonged to different populations, which increases the risk of detecting genetic differences not associated with longevity. It is also necessary to conduct a similar study for different ethnic groups (at the moment, the results are obtained only for Europeans).