Gene seems to make men bigger, but shortens their lives
A gene carried by both men and women—but active only in men—seems to grant them bigger bodies, but shorter lifespans, according to a new study from the Tokyo University of Agriculture. Working with mice, scientists have identified the gene, which is present in male sperm. Researchers created mice with genetic materials from two mothers, and no father, by manipulating DNA in mouse eggs so genes acted like those in sperm. This material was then implanted into the eggs of adult female mice, creating embryos; the offspring, which had no genetic material inherited from a male, lived on average one-third longer than normal mice. They were lighter and smaller at birth, but seemed to have better functioning immune systems, too. While the gene is passed on to both sexes, it’s silenced in females through a process known as imprinting.”We have known for some time that women tend to live longer than men in almost all countries worldwide, and that these sex-related differences in longevity also occur in many other mammalian species,” lead researcher Professor Tomohiro Kono told the BBC. “However, the reason for this difference was unclear and, in particular, it was not known whether longevity in mammals was controlled by the genome composition of only one or both parents. Our results suggested sex differences in longevity originating at the genome level, implying that the sperm genome has a detrimental effect on longevity in mammals. The study may give an answer to the fundamental questions: that is, whether longevity in mammals is controlled by the genome composition of only one or both parents, and just maybe, why women are at an advantage over men with regard to lifespan.”