Scientists have discovered key brain differences between men and women

REVOLUTIONARY DISCOVERY: MALE AND FEMALE BRAINS ARE RADICALLY DIFFERENT AT THE GENETIC LEVEL

The scientific community has documented unprecedented differences in the functioning of genes in male and female brains. Hundreds of genes demonstrate different activity depending on gender, which may be directly related to diseases with pronounced gender imbalance – including Alzheimer's disease and Parkinson's disease. Researchers have established that these differences are formed at the embryonic stage and are found in all primates, confirming their evolutionary antiquity. This is reported by The Conversation portal.

Scientists have been recording structural and functional differences in the brains of men and women for decades. However, only now, thanks to modern methods of transcriptomic analysis, has it become possible to determine how much these differences are due to genetics rather than environmental influences and learning. By measuring mRNA levels, researchers can precisely determine which genes are activated or suppressed at a specific moment.

A large-scale comparative study in 2017 revealed that about one-third of the entire human genome (out of 20,000 genes) exhibits sex specificity in at least one tissue of the body. The most striking differences are observed in reproductive organs, but impressive differences have also been found in the brain. The latest research has identified 610 genes with increased activity in the male brain and 316 in the female brain.

Notably, most genes with sex differences are located not on the sex X or Y chromosomes, but on regular autosomes, identical in both sexes. This indicates regulation of their activity by sex hormones. However, analysis of 266 embryonic brains showed that already at early stages of development, more than 1800 genes are more active in boys and about 1300 in girls. Such differences arise before the formation of sex glands, indicating a direct influence of sex chromosome genes on brain development.

The functional significance of these differences is only beginning to be revealed. In the female brain, increased activity of genes associated with neuronal function is more often observed, while in the male brain – genes responsible for maintaining cell membranes, nucleus structure, and other basic processes. Many differences are localized in specific brain areas, which may indicate their role in the formation of specific cognitive or behavioral functions. Scientists note that not all differences at the mRNA level are necessarily reflected at the protein level – cells may compensate for these changes.

Of particular interest is the potential connection between sex differences in gene expression and the uneven prevalence of neurodegenerative diseases. Many genes associated with Alzheimer's disease show increased activity in the female brain, which may explain the higher risk of the disease in women. In experiments on mice, it was found that the expression of the male SRY gene exacerbates the course of parkinsonism.