Why do women live longer? For many years, the scientific community has sought to clarify why females live longer than males in most species, and many biological and psychosocial factors have been taken into account, which although now a statistically proven fact, the reasons are still unknown.
A study from the University of California, San Francisco has just published data highlighting the second X chromosome, which can be revealed as the great secret of longevity and why women live longer.
- This research puts on the table the importance of X chromosomes.
- Without which life is not possible.
- Unlike what is observed on Y chromosomes.
- Which contain few different genes and are limited to the creation of physical characteristics.
- Such as male or facial genitalia.
- Hair.
- But are not necessary for survival.
Therefore, this factor may begin to explain why life expectancy is longer in women.
The fact that women live longer seems to be related to the second X chromosome.
The lead author of this study is Dena Dubal, professor of neurology at the University of California, San Francisco. The findings were published in the scientific journal Aging Cell. The research was conducted on a group of laboratory-raised experimental mice.
Rats were created genetically identical, with the exception of their sex chromosomes. The research was conducted with four different groups: the first and second groups were composed of XX mice with ovaries and XY mice with testicles; the third and fourth groups were artificially created as XX with testicles and XY with ovaries.
The study showed that mice carrying the XX chromosome lived longer than XY carriers, had ovaries or testicles or not. In addition, they also demonstrated that of all XX carriers, the most durable were those with ovaries.
They lived well beyond the average age in mice, i. e. the most durable combination was rats with ovaries and chromosome XX, the same ones created by the natural order, followed by XX mice with testicles, which did not survive long. beyond the half-life of a rat.
Both survived all carriers of the XY chromosome. Life expectancy in rats with chromosome XX with ovaries has reached 30 months, when the average of an XY rat generally does not exceed 12 months of life.
“For a longer lifespan, rats must have ovaries with two XX chromosomes, according to the natural order,” said Iryna Lobach, assistant professor of epidemiology and biostatistics at UCSF and co-author of the study.
The X chromosome, used by both women and men, is crucial for survival; contains many brain-related genes; In addition, the presence of recessive pathological mutations in a microsome X gene makes men more vulnerable to hereditary pathology.
For a woman to develop recessive pathology in a microsome X gene, two copies with a pathological mutation are needed, while in men only one copy is needed.
It appears that on an X chromosome there are six times more intelligence-related genes than on the rest of the chromosomes, so if one gene fails, this deficiency is complemented by the second X chromosome, while in males this substitution is not possible. .
Studies prior to those conducted by Dr. Dubal have already argued that this may explain why there is between 30% and 50% more intellectual disability in men. This conclusion was recently published by Gillian Turner and Michael Partington of the Prince of Wales Children’s Hospitals in Sydney and the western suburbs of Newcastle, both in Australia.
It is unclear what the second X chromosome brings to life expectancy, but it has been shown that it is heavily involved in the longevity of humans who carry it. On the other hand, the researchers say that this discovery does not negate environmental and social factors. -cultural influences that affect life expectancy.