Khaberni - A new scientific study has revealed that hundreds of genes in the human brain work differently between males and females, enhancing the idea that genetic differences, not just hormonal or environmental ones, play a fundamental role in shaping behavior and neurological functions, and perhaps in susceptibility to diseases like Alzheimer's and Parkinson's.
Genetic differences from early developmental stages
The study, prepared by Professor Jenny Graves from La Trobe University in Australia and published on ScienceAlert, explained that genetic differences in the brain appear from the earliest stages of fetal development, even before the formation of reproductive organs or the secretion of sex hormones.
Researchers examined brain tissues from human fetuses after their death and found more than 1,800 genes more active in male fetuses compared to 1,300 genes more active in females, patterns that later match what is observed in adult brains.
Broad Results in human and monkey brains
Analyses of the "transcriptome," which is a record of genetic activity in cells, showed that about 610 genes are more active in male brains, compared to 316 genes in females. Interestingly, these differences are not limited to genes located on the sex chromosomes "X" and "Y"; about 90% of the sexually biased genes are on normal chromosomes shared by both sexes, indicating the existence of subtle control mechanisms regulating their function, likely including sex hormones like testosterone and estrogen.
The study did not stop at humans; similar patterns of genetic activity were found in the brains of monkeys, mice, and even worms, suggesting that these differences are ancient and date back to common ancestors more than 70 million years ago.
Do brains really work differently?
In this context, Graves said it is too early to conclude that these genetic differences mean differences in intelligence, thinking, or cognitive abilities between the sexes, but she confirmed that differences in genetic expression of this magnitude must reflect on some neurological functions.
Graves also explained that the genes more active in female brains are associated with neural communication and interaction between nerve cells, while the active genes in male brains are more related to membrane structures and cell nuclei, pointing to subtle functional differences between the sexes in the structural organization of the brain.
Association with neurological diseases
The study saw these genetic differences as potentially explaining the different rates of occurrence of some neurological disorders between men and women. Many genes associated with Alzheimer's disease were found to be more active in females, which might explain the doubled rate of incidence among women compared to men.
In Parkinson's disease, previous studies have shown that a gene known as "SRY," which is found only in males, could exacerbate the severity of the disease when activated within the brain.
Deeper effects than we think
Researchers pointed out that these results confirm that the differences between the sexes in the brain are not superficial nor entirely acquired; they extend to the level of genes and cellular processes. However, they add that differences in genetic activity do not necessarily mean differences in the final output, as cells may balance differences through compensatory mechanisms to maintain stability of proteins and neurological functions.
Graves concluded that the biological distinction between male and female brains is a global evolutionary phenomenon that includes nearly all vertebrates, and understanding these differences will help in developing more precise treatments for neurologically distributed diseases with different gender distributions.
