Sex Chromosomes and Sex-Linked Traits
Inheritance on the sex chromosomes
Sex chromosomes
In many animals, including humans, sex chromosomes help determine biological sex. Humans typically have two sex chromosomes, often written as or .
Sex-linked traits
A sex-linked trait is controlled by a gene found on a sex chromosome, usually the chromosome in humans.
Why this matters
Sex-linked inheritance can produce patterns that differ between males and females because they do not always have the same sex chromosome combination.
Common examples
| Pattern | Notes |
|---|---|
| Often associated with female biological sex in humans | |
| Often associated with male biological sex in humans | |
| X-linked trait | Gene located on the chromosome |
In humans, a common sex chromosome pair for males is:
Humans typically have chromosomes in male biological sex.
Correct answer: XY
What is a sex-linked trait?
Sex-linked traits are carried on the or chromosome.
Correct answer: A trait controlled by a gene on a sex chromosome
Many sex-linked traits in humans are found on the:
Most classic sex-linked traits are -linked.
Correct answer: X chromosome
Why can sex-linked traits show different patterns in males and females?
Different chromosome combinations can change whether a recessive allele is expressed.
Correct answer: Because males and females may have different sex chromosome combinations