Scientists from the University of California in San Francisco, United States, have published a discovery that could be crucial to explain female longevity.
Across the world, women live longer than men, tends not to be unique to people, because it is also in most animal species.
Now, researchers say that the cause of this phenomenon would be the important role made by the second X chromosome that is present in mammalian women. This chromosome contains many genes that are related to the brain and are essential for survival: without at least one X, an animal can not live.
On his part, chromosome Y, which is only present in men, does not need to survive and contains very few genes other than those that create secondary sexual characteristics, such as male genitalia and face hair.
In experimenting them, the team adjusted the chromosome mice combinations. Apart from the blends that can be seen in nature – they use XX chromosomes with ovaries and XY men with two laboratory combinations with insects: men with XX chromosome with chests and women with XY chromosome with ovaries.
The mice were genetically similar, apart from their sex chromosomes, and grew in the same environment. Similarly, those with two X chromosome were living longer than those with X chromosome and one Y chromosome.
The mice that had a combination of XX chromosomes and ovaries were those who lived most. On the other hand, the combination of XX in the men with ceramics protects the animals from premature death, but did not extend their life beyond normal expectation.
"Those who had a XX combination escaped from premature death"
"For longer, mice had to have ovaries and XX chromosomes," said Iryna Lobach, one of the co-authors of the study. "But in terms of living a normal life, it was not important if they had ovaries or tests, those who had a XX combination escaped from premature death during aging," emphasized the researcher.
The study needed to be carried out a number of years because the mice were observed for 30 months, during the period they died or survived. It began to reflect the benefits of having two chromosome X when the animals were 23 months or older. (Source: RT).