Human sex chromosomes originated from a pair of autosomes, the ordinary or non-sex chromosomes that contain the majority of our genome and come in identical pairs. That ancestral pair of autosomes diverged to become two different chromosomes, X and Y. Even though X and Y have grown apart from each other and taken on unique functions—namely, determining sex and driving sex differences in males and females—they also retain shared functions inherited from their common ancestor.

New research from Whitehead Institute Member David Page, who is also a professor of biology at the Massachusetts Institute of Technology and a Howard Hughes Medical Investigator, and postdoc in his lab Adrianna San Roman sheds light on the sex chromosomes' shared role as influential gene regulators.

The research, published in Cell Genomics on December 13, shows that genes expressed from the X and Y chromosomes impact cells throughout the body—not just in the reproductive system—by dialing up or down the expression of thousands of genes found on other chromosomes.

Furthermore, the researchers found that the gene pair responsible for around half of this regulatory behavior, ZFX and ZFY, found on the X and Y chromosome respectively, have essentially the same regulatory effects as each other. This suggests that ZFX and ZFY inherited their role as influential gene regulators from their shared ancestor and have independently maintained it, even as their respective chromosomes diverged, because that regulatory role is critical for human growth and development. The genes regulated by ZFX and ZFY are involved in all sorts of important biological processes, showing that the sex chromosomes contribute widely to functions beyond those related to sex characteristics.

You can read the full story in an article by Greta Friar published in the phys.org web site at: https://phys.org/news/2023-12-sex-chromosomes-responsible.html.