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Researchers: Longevity depends on few genes

A study of centenarians points to chromosome 4 as a contributor to longevity

by Tamara Traubman
Mildred Tilton, an American who lives in the city of Luminster on the banks of the Hansheva River in the state of Massachusetts, recently celebrated her 102nd birthday. Her father, Malcolm Brown, lived to a ripe old age. 101 Tilton has two sisters who are still living: Lois Dickinson, 99, and Marjorie Fisher, 97. All three sisters have a younger brother: Roger Brown, 92.

Apart from Dickenson, who is in a nursing home, the health of the other family members is definitely good: they are independent and still lead an active lifestyle. Two Boston scientists who analyzed the DNA of this extraordinary family, as well as dozens of other 90- and 100-year-olds, believe they have cracked part of the mystery of their longevity.

The researchers, Dr. Louis Kankel and Dr. Tom Perles from Harvard University Medical School, reported yesterday that they found a specific region in the DNA that contains genes that probably contribute to longevity.

Kankel and Perles' research began in 1995. They interviewed people who had arrived at an extreme shiva in reasonable health, as part of a study known as the "New England Centenarian Study". During the interviews, many participants said that they have a sibling or several siblings who are 90 or older. In an official announcement issued by Harvard University, Dr. Kankel wrote that "often times, after you find a centenarian, you will find that he has at least one first-degree relative who is also a centenarian or in his 90s, and in excellent health." This finding led the researchers to the conclusion that longevity has a genetic component.

If future studies confirm the results of the present study, this discovery will be important for the study of aging. This is what Dr. Thomas Kirkwood, a gerontologist from the University of Newcastle in Great Britain, told the scientific journal "Science" in an issue that will be published on Friday. But he warned that "the results are not very clear", and therefore it is too early, in his opinion, to get excited about the findings.

Dr. Kirkwood added that it is possible that the genes in the area are not directly related to longevity, but rather those that provide protection against diseases associated with aging, such as heart disease and Alzheimer's.

To test the hereditary basis of longevity, the researchers scanned the genomes of 137 pairs or triplets of brothers and sisters, in which there is at least one brother who is 98 years old or older, and another brother who has passed the age of 90. A total of 308 people, aged 91 to 109, were tested. Most The participants, the researchers say, are of European descent.

In an attempt to find a genetic common denominator for people who live longer, the researchers marked 400 regions along the genome of the subjects, and compared the genomes to each other. They discovered that almost all of the subjects had a similar segment on chromosome number four. Dr. Kankel and Dr. Perles believe that somewhere along this section, there is a gene or a few genes that contribute to longevity.

In an article describing the results of the research, which was published yesterday in the scientific journal "Sciences of the National Academy of "Proceedings, the researchers write that they believe that the genes found in the area are directly related to a long life span, and not only provide some protection against the diseases associated with aging.

However, the process of finding the specific genes can take a long time. In the section that the researchers focused on, there are between 100 and 500 genes. According to the conventional wisdom among aging researchers, there must be about a thousand genes - spread over the entire genome, and not clustered in one region - that are related to longevity, because it is a complex trait.

But Dr. Kankel suggests that longevity may be influenced by only a few genes. It is based on research that found that in organisms such as the fruit fly and a tiny worm called a nematode, changes in a single gene can extend lifespan by tens of percent. At the end of last year, for example, scientists from the University of Connecticut made in the fruit fly a change in a gene that was named INDY, an acronym for "I'm "Not Dead Yet" (I'm not dead yet). This single change increased the fly's lifespan by 50%, allowing it to live 110 days. This, while his usual friends survive 70 days at most. "We knew that only a few genes affect longevity in poor organisms," says Dr. Kankel, "now we think that this may also be true for humans."

Dr. Kankel says that he and his colleagues are not interested in finding a way to give people immortal life, but only to allow people to grow old without the diseases that accompany old age. "We see that the centenarians in our research age slowly compared to the general population, and they somehow manage to significantly postpone, and sometimes even avoid completely, the diseases associated with aging such as heart disease, stroke, diabetes, cancer and Alzheimer's," says Dr. Kankel. "We are not trying to find the fountain of youth," adds Dr. Perles. "We are trying to find the source of good aging".

According to Dr. Perles, it is possible that people who reach an extreme age benefit from a successful genetic combination, which includes genes for longevity and the absence of damaged versions of genes that increase the chance of suffering from diseases such as Alzheimer's and cancer.

In any case, it is still not clear what is the contribution of heredity and what is the contribution of the environment and lifestyle to life expectancy. The results of a study on Scandinavian twins, who did not reach an extreme age, imply that the share of heredity for an extreme life is about 25% and the remaining 75% is probably responsible for the lifestyle. But it is not certain that this attitude is also true for the centenarians. "It is possible that at these ages the genetic factors become more significant", believes Dr. Perles.

^^Slim, don't smoke, not nervous^^

The participants in the "New England Centenarian Study" lead very different lifestyles: some are devout vegetarians, others consume high-fat foods; Some are learned, others are barely literate; Their income level is varied; And the physical activity they usually do ranges from long hours of lounging on the couch to a daily run around the park.

But the researchers nevertheless found some common characteristics in their lifestyles: few of them are obese and few of them smoke. In addition, preliminary research suggests that in personality tests that test the level of neuroticism, the life extenders received low scores. The meaning of a low score, the researchers say, is that the subjects do not obsessively dwell on problems, and are therefore able to cope well with stressful situations.

2 תגובות

  1. According to the research, longevity is a function of the nervous system [Kenyon C. 1998] and in humans it is a behavior and it seems that longevity matters for things and they are whether a person is looking for his own way, is he looking for God and is he choosing a good goal that is good for all of creation and not just for him Or for a finishing group, and if you have any information about studies on the connection between spirituality and longevity, I would be happy to know, thank you Dr. Shabsky

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