Female mammals typically carry two X chromosomes — one from each parent — and a new study suggests that the maternal X is linked to faster brain aging.

Rett syndrome is a genetic condition that mostly affects girls. It is caused by a defective MECP2 gene located on the X chromosome. This gene contains instructions for the synthesis of MeCP2 protein.

Since these fossil chromosomes came from a woolly mammoth, one of the first steps was to try and determine the number of chromosomes that this animal had when it was living.

Other chromosomes, hormone receptors, neural pathways, reproductive organs and environmental factors contribute to sex determination as well, not unlike an orchestra with its ensemble of instruments.

Freeze-dried chromosomes can survive for thousands of years They contain unprecedented detail about their long-dead parent organisms ...

Researchers have uncovered which genes on the Y chromosome regulate the development of sperm and impact fertility in male mice. This research could help us understand why some men don't ...

Researchers have identified a sex chromosome in the California two-spot octopus. This chromosome has likely been around for 480 million years, since before octopuses split apart from the nautilus ...

Once dismissed as “junk” DNA, ancient viruses embedded in the human genome play a key role in early human development, ...

From Australian birds to human clinics, the science keeps pointing to the same conclusion: Sex is a spectrum, not a switch.