Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The Y chromosome is one of the two sex chromosomes in humans. It's smaller than the X chromosome and carries fewer genes. Males have both an X and a Y chromosome, while females have two Xs.
Related terms
SRY Gene: This gene on the Y chromosome triggers male sexual development.
Sex Determination System: This system determines whether an organism will develop into a male or female based on its set of sex chromosomes.
Hemizygous Trait: A trait where there's only one allele present instead of two; for instance, all traits on the male’s single copy of his x or y-chromosome would be hemizygous.