Life expectancy largely depends on 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: after studying 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 from Boston University have applied a widely used genetic screening technique to search for genetic sequences that occur in centenarians — people aged 100 or more years.
In addition to a potential way to predict who will be able to live to the hundredth birthday, the study demonstrates the significant influence of genetic factors on life expectancy. The researchers hope that identifying genes and the corresponding molecular mechanisms that contribute to longevity in the future will help delay or prevent various age-related diseases, such as heart disease, Alzheimer’s disease and even cancer.
Previous results of the world’s largest project to study centenarians have shown that 90% of them continue to lead a full life before the age of 93, avoiding diseases leading to disability. Also interesting is the fact that centenarians on average have the same number of genetic variations associated with any diseases as people in the control group. This suggests that life expectancy does not depend on the absence of a genetic predisposition to diseases, but on the genes that determine longevity.
The findings also cast doubt on the reliability of genetic tests conducted to calculate the individual risk of a particular disease (for example, type 2 diabetes mellitus 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.
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 that occur much more often in the group of centenarians. Each of these variations individually played a minor role, and scientists have developed a computer model that allows us to identify the cumulative effect of various genetic variations. Based on the list of genetic variations that are most different in the study and control groups, the scientists identified 150 of them that give the highest prognostic value.
This model is able to “guess” a centenarian in 77% of cases, the reason for the longevity of the remaining 23% may be both unrecorded genetic factors and environmental influences that are not taken into account during modeling. People over the age of 108 had the largest number of isolated genetic variations.