Hereditary predisposition to a long life
Polymorphisms of longevityNikolai Gorodetsky, "Газета.Ru ".
Scientists have discovered genetic variations responsible for human longevity. In case of successful verification of the results of this study on a sufficiently large group of people (numbering significantly more than a thousand), it will be possible to talk about the emergence of a real method of ensuring human longevity.
If we abstract from accidents, accidents, epidemics, bad habits and other "falling bricks", it can be argued that a person is an organism capable of functioning for a certain amount of time without serious failures. But for each person, this number is different: it is known that very young people can suddenly die of a heart attack, and some centenarians who do not particularly monitor their health successfully overcome the centennial milestone. Official science cannot yet reliably answer the question of why this is happening.
In order to somehow clarify the problem of longevity, an international group of scientists led by Paola Sebastiani from Boston University suggested that people who have successfully lived to an advanced age may be carriers of the corresponding genetic variations.
To this end, scientists studied the genetic material of 1,055 people whose age was at least 95 years. The obtained data were compared with the material from the control group of 1,267 people. The results of the work are published in an article in the new issue of the journal Science (Paola Sebastiani et al., Genetic Signatures of Exceptional Longevity in Humans; a popular retelling of the results can be read in the press release of Boston University Researchers Identify Genetic Signatures of Human Exceptional Longevity - VM).
The assumption of scientists that healthy old people in body and spirit have certain genetic variations turned out to be correct.
Initially, researchers were able to detect 70 genetic variations (single-nucleotide polymorphisms) that correlated with an increase in life expectancy. Upon repeated analysis, this number was reduced to 33. Then the scientists analyzed the cumulative effect of genetic variations on the probability that a person would live to be a hundred years old. As a result of this work, scientists have obtained 150 single-nucleotide polymorphisms that may be responsible for a long human life.
Based on the data obtained, scientists have developed a method that allows predicting the possibility of longevity for a particular person. According to the researchers, the probability of success of such a forecast is quite high and is 77%. (Soon this program will be available on the website of the New England Centenarian Study project – V.M.)
In the course of an additional analysis, the authors of the work showed that 90% of all centenarians can be divided into 19 different groups, which are characterized by different combinations of genetic variations. In particular, these groups differ in the frequency of certain diseases, the age of a person in which he has diseases such as dementia (dementia) and high blood pressure.
A big surprise for scientists was the fact that the predisposition to longevity is completely unrelated to the absence of genetic variations that are responsible for a person's predisposition to diseases.
According to the study's lead author Paola Sebastiani, the results published in Science need to be confirmed by analyzing more numerous groups of people. But there is reason to believe, says the expert, that the key to artificial longevity is not to fight specific diseases, but to artificially enrich the human genetic material with appropriate polymorphisms. Probably, it is their combination that makes it possible to overcome diseases and the risks associated with them.
However, James Vopel, director of the Max Planck Institute for Demographic Research (Rostock, Germany), commenting on the results of the work, expressed fears that due to the successful results of geneticists, the negative impact of the environment on life expectancy may go out of public attention. "Several hundred "good" genes do not guarantee a person with a 77 percent probability that he will live to a very old age, and I am concerned that this statistic may be misinterpreted," the scientist says.
From Irina Yakutenko's comments to the article with the unfortunate title "Longevity genes found", published in the Snob magazine:
How did scientists unearth markers of longevity and why shouldn't they be called "genes"? Deciphering the genomes of 1,600 centenarians and finding "longevity genes" in their DNA is a task impossible in a reasonable time even today. However, an article from the journal Science says that they conducted a genome-wide screening of all patriarchs and found as many as 150 genetic markers that increase the likelihood that a person's biography will last a century.
It seems that this task is more difficult than the notorious search for a needle in a haystack: firstly, scientists did not know which markers they needed, and secondly, the human genome contains about 130 thousand genes, and multiplying 130 thousand by 1600 gives an absolutely unimaginable figure. Nevertheless, in recent years, tasks like this have been solved everywhere. Experts have found an excellent tool that allows them to pull the necessary sequences from the genome in much the same way as a magnet pulls a needle out of a hay. This tool is called the funny word "snip". It comes from the English abbreviation SNP (single nucleotide polymorphism – single nucleotide polymorphism).
Snip is a mutation in the genome that affects only one of its "letters" – the nucleotide. So, the words "century" and "staletie" differ by just one letter. Replacing "o" with "a" is the snip. In our example, the mutation obviously made the word wrong, but in nature, many mutations do not affect the work of genes and may generally be to the right or left of them on the chromosome. But at the same time, there are snips linked to certain states of a particular gene. It is much easier to identify which snips a person has than to find whole genes (genes "linked" with snips can then be relatively easily found using routine experiments). That is, today we have found 150 longevity snips in the genome, which means that tomorrow we will find the genes we need.
The authors of the new work checked the genomes of centenarians for the presence of 295 thousand snips – these are, in fact, all mutations known to medicine that may be of practical importance. In parallel, scientists were looking for the same snips in the DNA of people from the control group, which was typed randomly. It turned out that the record holders for the number of years lived with a much higher frequency than the average, carry 150 certain snips in their genes. Moreover, a potential centenarian does not necessarily have to have all one and a half hundred "longevity SNPs" – scientists have identified 19 groups, representatives of each of which mainly carried certain combinations of snips. (A particular centenarian does not have to have all 150 mutations. There are noticeably fewer mutations in each of the 19 groups of record holders.)
Some combinations were found in people who had typical age-related diseases (Alzheimer's disease, problems with the cardiovascular system, senile dementia) manifested much later than the prescribed age, even among centenarians, other combinations were present in those who simply continued to live despite ailments.
By the way, it is this ability to overcome ailments or prevent them from developing that seems to be "encoded" in the "longevity snips". The researchers tested centenarians for snips, the presence of which, as previously established, increases the chance of certain diseases, and were surprised to find that there are as many of them in record holders as in ordinary people. That is, "longevity snips" somehow neutralize the effect of "bad" genes and make their owners more resistant to diseases. One very important conclusion follows from this fact: in genomic medical research, which is gaining more and more popularity, it is impossible to consider the results of tests for "bad" snips separately from the rest of the genomic "background", which can weaken or completely negate their negative impact.
Portal "Eternal youth" http://vechnayamolodost.ru05.07.2010