(ORDO NEWS) — Stanford scientists have found thousands of genes with different levels of activity in the brains of male and female mice, as well as more than six hundred genes that change their activity at different stages of the female reproductive cycle. The researchers suggest that similar differences may be present in the brains of men and women.
The social behavior typical for the sex of females and males of the same species is necessary for its survival and has been honed by evolution over millions of years. Therefore, the key reactions are “built-in” into the brain of animals at the genetic level.
For example, male mice can very quickly determine the sex of another individual and initiate either mating when they meet a female, or a fight if another male invades their territory. For females, on the contrary, territorial aggression is less typical, but they are ready to protect their cubs at any cost.
In a new paper, scientists from Stanford University in the US decided to investigate how gene activity in brain cells affects gender-specific behavior in mice. They focused their attention on a population of sex hormone-responsive neurons drawn from four different brain structures involved in sexual behavior.
In each of them, they determined the level of gene expression and looked for statistically significant differences between the sexes. As a result, scientists identified 1415 genes with a significant difference in the level of expression between the sexes or estrous states – phases of the estrous cycle , that is, a set of regularly repeated changes in the reproductive system in female mammals.
Interestingly, some of the found genes with different levels of activity are associated with the risk of developing brain diseases that are more characteristic of one of the sexes: for example, autism spectrum disorders are four times more common in men, while Alzheimer’s disease and multiple sclerosis affect women more often.
The authors of the article suggest that the destructive effect of a mutation in a particular gene depends on its level of activity: the mutation will cause more problems for the sex in which this gene is very active than the opposite, in which this gene is almost not expressed.
In addition, the frequency of migraines, epileptic seizures, and psychiatric disorders can vary throughout the menstrual cycle, and the results of the new work may help uncover the biological basis for these changes.
Although mice are evolutionarily quite distant from humans, the brain structures studied are common to all mammalian brains, so the researchers suggest that there are similar differences in the brains of men and women.
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