Why women live longer?

One gene helps men have bigger bodies than women, but reduces their lifespan, Japanese scientists concluded.

Scientists from Tokyo Agricultural University (Japan) apply cloning techniques to create pups without male specimens. To do that, they act on DNA in mouse eggs to perform DNA-like functions in sperm.

The team introduced modified DNA into the eggs of two adult female mice to create embryos. So the pups do not inherit any male genes. They are lighter and smaller than those that inherit genes from both parents, but have an average life expectancy of 33%. In addition, the "no father" mouse's immune system works more efficiently than the "daddy" group.

Experts found the "father" group had something that the other group did not have. That's the gene called Rasgrf1 . This gene is transmitted from the father's body to the baby, but it is turned off in female mice and only works in male mice. Scientists claim that Rasgrf1 increases the size of the male body but does not cause any effect on the female.

Professor Tomohiro Kono, the leader of the study, said: "We know that women tend to live longer than men. A similar situation also occurs in many other mammals. This trend is still a controversial issue, and our study shows that the life difference in males and females is derived from genes, namely genes in sperm, because they do not carry Rasgrf1 gene. but female mice have smaller bodies, but live longer " .

Genome construction is one of the reasons women have a longer life expectancy than men.Photo: corbis.com.

The team said that in nature males have to compete with each other to win the chance to mate with females. In such wars, the advantage is usually those of big and strong bodies. So the majority of nutrients in the male body are reserved for muscles and bones. On the contrary, females tend to save energy for pregnancy and raising children. So their bodies are smaller than males.

Although the study was conducted with rats, Professor Kono and colleagues believe their results are true for all mammals, including humans.

Dr. Allan Pacey, an animal reproduction expert at the University of Sheffield, said: "The results of the University of Tokyo study are very remarkable, but this is a problem that needs to be investigated. nor should the illusion that one day humans can extend their lifespan by acting on genes. "

Professor Kay-Tee Khaw, an aging expert from Cambridge University, also said that the research results of the Kono group are not necessarily applicable to people.

"The difference in sex life in people varies with time and environment. I don't think we can explain that difference with a single gene , " Khaw said.