The Y chromosome is one of the two sex chromosomes that are involved in sex determination. Humans and most other mammals have two sex chromosomes (X and Y) that in combination determine the sex of an individual. Females have two X chromosomes in their cells, while males have one X and one Y.
Y chromosome. Humans and many other mammals have one pair of sex chromosomes in each cell. Females have two X chromosomes while males have one X and one Y chromosome. The Y chromosome is very small. It likely contains 50 to 60 genes and represents 2% of a cell's total DNA. Because only males have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and development.
Former Associate Investigator
Division of Intramural Research