Despite their critical importance for understanding disease prevalence and severity, it was only recently that differences in gene expression between the sexes in humans or other placental mammals received serious attention in the scientific research community.
Melissa Wilson, a researcher at the Biodesign Center for Evolutionary Mechanisms, the Center for Evolution and Medicine, and Arizona State University's College of Life Sciences, reviewed the latest research published in the journal Science that examined patterns of gender differences in gene expression. Across the genome.
This massive effort began with an ambitious project a decade ago, known as the "Genetic Tissue Expressions Consortium" (GTEx), which aimed to discover how DNA variation affects gene expression across a range of human tissues. The pioneering journal published a special issue on September 11th. This September for this topic.
Researchers have discovered that more than one-third of genes exhibit gender-biased expression in at least one tissue, and the most recent studies published in the Special Issue discuss the association of gene expressions, the effects of gene regulation in human tissues, the identification of rare functional genetic variation, the study of predictors of telomere length, and specific gene regulation. By cell type.
Men are from Mars and women are from Venus
The difference between the female and the male in mammals, and especially humans, has occupied scientists for a long time, but since the publication of the book "Men from Mars and Women from Venus", written by American psychiatrist John Gray and published in May 1992, this biological difference has taken new dimensions.
The book dealt with the problems that may occur between men and women as a result of the psychological differences between them, and it was very successful, and millions of copies were sold from it.
But on the other hand, previous studies focused on the clear differences between the brains of men and women and on the areas of the brain that were previously thought to highlight differences based on gender.
Neuroscientists have viewed sex hormones as the key to sexual difference in the mind, and despite their importance, there is a growing body of evidence indicating that gene expression depends on interactions between genetic, environmental and non-genetic factors that influence each other in complex ways.
Maps of gene expression values show how experimental conditions affected the expression of a group of genes and green indicates decreased expression (Miguel Andrade-Wikipedia)
A gender-biased expression
Recent findings also indicate that sex-related variances in gene expression are much more prevalent than previously assumed, with more than a third of genes showing gender-biased expression in at least one tissue.
The research describes the regulatory differences between genes between the sexes, sheds light on the apparent differences between them in health and disease, and shows that differentially expressed genes strongly influence the risk, incidence, spread and severity of many diseases.
Most of the traits that show contrast between males and females appear to result from differences in the expression of common genes, and not through the expression of genes on chromosomes or sex hormones.
"One of the most surprising things about this comprehensive study of gender differences is that while overall differences span the genome and contribute to biases to human health, each individual gene varies greatly between people," Wilson said in a press release on the University of Arizona website.
The Genetic Tissue Expressions Consortium (GTEx) project demonstrated how DNA variation affects gene expression across a range of human tissues (US National Institutes of Health)
Imprints of the distant past
It is possible that these traits evolved, the researchers think, and the appearance of placental mammals about 90 million years ago may have led to differences in immune function between males and females, they claim.
Such gender-based differences have left their mark on current mammals, including humans, and have been shown to have higher rates of autoimmune disorders in females and increased rates of cancer in males.
Researchers have identified hundreds to thousands of genes expressed for each tissue that show gender differences in gene expression, and they hypothesize that this gender difference appears in the formation of a cell type - particularly immune-related cells - and may contribute to a defect in the basic qualitative regulation of some diseases.
The method used in the "Genetic Tissue Expressions Consortium" project to study the effect of DNA variation on gene expression across a range of human tissues (François Ajue et al-Wikipedia)
These studies provide a comprehensive baseline for gender differences in gene expression in uninfected tissues, and may also indicate the most important pathways for gender differences in aetiology, and aid in the development of targeted therapies.
A better understanding of these sex-related variations in the behavior of our genes could improve diagnosis and treatment for a wide range of human diseases.