A group of scientists from the United States discovered what is behind the survival of women. Apparently X chromosomes cause women to be longer than men, and it is essential to survive.
The studies conducted at the University of California-San Francisco (UCSF) in California believe that the second X chromosome is in length and other benefits.
"X chromosome has several genes related to the brain and is essential for survival. At least X can not survive. Y chromosomes, only those of men, only produce genes such as male genitals and facial hair, which produce secondary sex sequences, and There is no need for survival, "said press releases at this university.
In the laboratory, the researchers gave mice (female and male) to the four combinations of chromosome and gonad, with two natural (XX ovaries and XY testulates) and two produced (XX testes and XY ovarian).
Animals were the same and lived in the same environment, except for sex chromosomes.
Long-lived mice have XX chromosomes in the ovaries.
"For a long time, I have asked for survival for females," said Dena Dubal, the author of research published in Aging Cell.
"A person can imagine women who have evolved in this way. When you are born, you can guarantee the well-being of your children, maybe your children," he said.
The research lasted for several years, seeing that 30-month-old mice did not see or die.
Female chromosomes and female gonads extended their lifestyle between 12 and 30 months, "middle ages in old age".
Most of the effects were in chromosomes, because the XX arrows were longer than XY and whether ovaries or testulates were present. However, longer mice were ovarian with XX chromosomes.
"This suggests that the hormones created by the female gonad are joining the mouse's life with two X chromosomes, how they develop the mouse or how certain biological life is affected," said Dubal.
The mouse genetically females (ovaries and testes) shared two different types and "two X and ovaries to keep the apples longer for 21 months, the normal life was to end the mouse."
To protect mice with "genetically feminine but hormonal masculine", he supported the second X chromosomes that had previously died.
According to Iryna Lobach, a part of the teacher and research, to be longer than expected, should be ovules and two XX chromosomes, but they had to live a normal life, because they did not have ovaries or testicles.
"During the twentieth century, they fled during their aging," he said.
Dubal said that "when they go wrong in old age, having X chromosomes and having a diversity of their expressions can be really beneficial."