In the 1980s, scientists knew little about the X and Y chromosomes. What they did understand was that every cell in the body contains 23 pairs of chromosomes. Each of these pairs is similar, except one. While females typically have two X chromosomes, males have one X chromosome and one Y chromosome. But which gene on the Y chromosome causes a developing embryo to become a male had remained an enticing mystery for geneticists worldwide.
At first, the X and the Y sex chromosomes seemed like an unlikely pair. But then, researchers, including Whitehead Institute Member David Page, began finding clues that suggested otherwise: identical DNA sequences on the X and Y chromosomes.
Soon, it became clear that the tips of the X and Y chromosomes join together in a tight embrace, swapping genetic material during the process of sperm production from immature male germ cells. This limited area of genetic exchange between the two sex chromosomes is called the pseudoautosomal region (PAR).
By Shafaq Zia, Whitehead Institute for Biomedical Research
Article can be accessed on: MedicalXpress