The chromosome may contain regions that promote their DNA’s spread by killing sperm that carry Y chromosomes. However, Y chromosomes may have evolved counter mechanisms over time
23 November 2022
Around 50,000 years ago, a new X chromosome appears to have been introduced into modern humans that had not long left Africa.
There was probably exceptionally strong selection for parts of this chromosome because, today, most people of less-recent African ancestry have inherited those regions.