The report by California University of San Francisco (UCSF) describes a second X chromosome that women have in relation to men, which is possible for a woman's longevity and other physiological benefits.
The human Y chromosome has some brain genes, and it is not necessary to survive, the study found.
Based on mouse experiments, researchers analyze the effects on mammals with two X chromosomes, compared to men with only one and the other Y.
Unlike the X-chromosome's biological wealth, only the masculine Y contains only a few genes that differ from secondary sexual features such as male genitalia and facial hair and are not necessary for survival. .
"We have long thought of what causes a woman's longevity," says researcher Dena Dubal, associate professor of UCSF neurology and a research journal published today in Aging Cell's scientific journal.
"We can imagine that nature has led women to develop this way, and as you live longer, you can ensure the prosperity of your offspring and, possibly, offspring," Dubal said.
The researchers compared laboratory poisons with four different chromosome combinations and gonads (a body that formed male or female gametes), two naturally occurring -XX ovaries and an XY test – and two in the laboratory.
In the manipulation of the gene, the combinations begin with XX chromosomes which were implanted in the ovaries and XY chromosomes in ovaries.
"The mice were genetically identical except for the chromosomes of the sexes, but everything else, including the environment, was the same," the study said.
The longest life was achieved in those mice with XX chromosomes in their ovaries, which exceeded the average life expectancy of 21 months and was up to 30 months.
The genes implanted in XX genes prevented premature death of animals, but they only extended life for one or two months.
"For longer ages, mice need to have ovaries with two XX chromosomes, naturally," summarizes Iryna Lobach, professor of biosynthesis and biosynthesis at ICSF, and co-author of the report.