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Scientists believe they have cracked the secret of aging.
A major genetic analysis of people, rodents, and fish found that the length of their DNA was directly related to their biological age.
Shorter genes were associated with shorter life expectancy, while longer genes were linked to better health and longevity.
Scientists believe that if they can hijack this mechanism, it could pave the way for a source of youth drugs that could slow, or even reverse, aging.
Dr Thomas Stoeger, lead author of the study from Northwestern University in Illinois, said: “I find it very elegant that a single, relatively concise principle seems to explain almost all of the changes in gene activity that occur in animals as they age. are reproduced”. years.’
Scientists said having longer genes can make someone live longer (file photo)
The length of a gene is based on the number of nucleotides it contains. Each chain of nucleotides is translated into an amino acid, forming a protein.
Therefore, a very long gene produces a large protein and a short gene produces a small protein. A cell needs to have a balanced number of small and large proteins to achieve homeostasis, and problems occur when that balance gets out of whack.
In the study, the researchers analyzed genetic data from several large data sets, including the Genotype and Tissue Expression Project, a tissue bank funded by the National Institutes of Health that archives samples from human donors for research purposes.
The research team first analyzed tissue samples from mice, rats and killifish of various ages.
In all the animals, the researchers noted subtle changes in thousands of different genes in the samples.
This means that not just a small subset of genes contributes to aging. Aging, on the other hand, is characterized by changes at the systems level.
This point of view differs from the prevailing biological approaches that study the effects of individual genes.
Since the inception of modern genetics in the early 20th century, many researchers have hoped that they could attribute many complex biological phenomena to single genes.
And while some diseases, such as hemophilia, are the result of single gene mutations, the limited focus on studying single genes has yet to lead to explanations for the myriad changes that occur in neurodegenerative diseases and aging.
After completing their animal research, the researchers turned their attention to humans. They looked at changes in human genes from ages 30 to 49, from 50 to 69, and after age 70 and older.
Measurable changes in gene activity according to gene length already occurred by the time humans reached middle age.
“It seems that something is already happening early in life, but it becomes more pronounced with age,” Dr. Stoeger said.
‘It seems that, at an early age, our cells can counteract disturbances that would lead to an imbalance in gene activity. Then all of a sudden our cells can no longer counteract it.
Northwestern’s Luis Amaral, lead author of the study, said: “The result for humans is very strong because we have more samples for humans than for other animals.”
“It was also interesting because all the mice we studied are genetically identical, of the same gender and raised in the same laboratory conditions, but humans are all different.
‘They all died from different causes and at different ages. We analyzed samples of men and women separately and found the same pattern.
But the scientists found that with aging, activity within cells shifts toward shorter genes, upsetting the balance.
This is counteracted in people with very long genes, because they have longer proteins available in the cells.
Dr Stoeger said: ‘Changes in gene activity are very, very small, and these small changes involve thousands of genes.
“We found that this change was consistent in different tissues and in different animals.”
The scientists hope that the study, published in Nature Aging, will spur the development of therapies to slow or reverse aging.
Today, medications target the symptoms rather than the causes of aging, which Northwestern experts say is like using pain relievers to reduce a fever.
Dr Amaral said: ‘Fever can occur for many, many reasons. It can be caused by an infection, which requires antibiotics to cure, or by appendicitis, which requires surgery.
Here it is the same. The problem is the imbalance of gene activity. If you can help correct the imbalance, then you can address the downstream consequences.’