GENES OF LONGEVITY: The Result of Mixed Marriages and Good Heredity
Photo by Alexander Grey on Unsplash
New scientific evidence suggests that genetics plays a much greater role in human lifespan than previously believed. A deeper understanding of the genetic mechanisms of aging is expected to help significantly slow this process.
GENETICS MATTERS MORE THAN WE THOUGHT
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ccording to a recent study published in the journal Science, approximately 55% of the observed variation in human lifespan is genetically determined. Previously, scientists estimated the contribution of heredity to longevity at only 10–25%. Israeli biophysicists from the Weizmann Institute of Science argue that earlier estimates were significantly underestimated due to methodological limitations. The problem was that previous studies did not effectively distinguish between deaths caused by external factors, such as infectious diseases or accidents, and deaths resulting from internal factors. The latter include, for example, the gradual decline of organ function caused by accumulated DNA damage. To identify these factors, the Israeli researchers analyzed a vast body of data collected from studies of long-lived twins dating back to the 1800s. It is well known that identical twins share 100% of their DNA, whereas fraternal twins and other siblings share approximately half of their genetic material.
NOT ALL DISEASES ARE INHERITED EQUALLY
By comparing the lifespans of identical and fraternal twins, the research team was able to model the heritability of longevity. In data from the late nineteenth and early twentieth centuries, when people often died young from infectious diseases, the genetic signal was virtually undetectable. However, by the middle of the last century, the estimated heritability of lifespan began to increase naturally. It became more apparent as public health measures improved and external causes of death became less dominant. At the same time, the researchers discovered that not all internal causes of death are inherited to the same degree. Dementia and cardiovascular diseases showed a high level of genetic predisposition. Cancer, by contrast, demonstrated lower heritability. This is likely because the development of cancer is more strongly influenced by random cellular mutations and environmental factors.
MEDICINE AND HEALTHY EATING HAVE NOTHING TO DO WITH IT!
The relationship between genes and lifespan is also being illuminated by data collected from “supercentenarians”, people who have lived beyond the age of 100. At the Human Genome and Stem Cell Research Center of the University of São Paulo, Brazilian scientists sequenced the genomes of more than 160 such individuals. All of them retained complete mental clarity. Many demonstrated truly remarkable achievements despite their advanced age. One example is a 106-year-old woman who took up swimming at the age of 70 and won her first competition when she turned 100. She is not the only long-lived person in her family. She has two younger sisters who are over 100 years old and an aunt who reached the age of 110. Another example is a 107-year-old man who still works full-time at a supermarket, sorting shopping carts. Then there is Sister Inah Canabarro Lucas, who was recognized as the world’s oldest living person before her death in April of last year at the age of 116. Like many others in this group, she did not restrict her intake of sugar or fats. Sister Lucas attributed her longevity to her love of chocolate.
THE PHENOMENON OF BRAZILIAN SUPERCENTENARIANS
Preliminary data suggest that people who reach the age of 100 did not necessarily follow especially healthy diets for most of their lives. Many also had limited access to regular physical exercise and high-tech medical care. In other words, the secret of their longevity may lie primarily in their genomes. Scientists have proposed a possible explanation: the phenomenon of exceptional longevity may be linked to genetic diversity. Brazil’s population is highly mixed in ethnogenetic terms, and this diversity may contribute to longer lifespans. Most participants in the Brazilian study have ancestry that combines European, African, and Indigenous American origins. By contrast, earlier studies, including those conducted in the United States, examined the health of long-lived individuals within more genetically homogeneous populations. To identify genetic variants associated with extreme longevity, researchers are comparing the genomes of the participants with those of individuals from an existing biobank who died of natural causes at a relatively young age. Scientists hope that these findings will lead to strategies that can benefit people who did not inherit the same fortunate combination of genes as the supercentenarians.
Оригинальные исследования:
- Longevity is in the genes: half of lifespan is heritable
- Still working at 107: supercentenarian study probes genetics of extreme longevity
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