Here's why:
* Non-autosomal chromosomes: These are the sex chromosomes, which determine an individual's biological sex. In humans, these are the X and Y chromosomes.
* Sex-linked inheritance: Genes located on these sex chromosomes are said to be sex-linked. Their inheritance patterns differ from those of genes on autosomes (the other 22 pairs of chromosomes) because males and females have different combinations of sex chromosomes (males: XY, females: XX).
This leads to some unique characteristics of sex-linked inheritance:
* Unequal inheritance: Males only have one X chromosome, so they inherit only one copy of a sex-linked gene. Females have two X chromosomes and inherit two copies.
* Different expression: Recessive sex-linked traits are more likely to be expressed in males, as there is no second X chromosome to potentially carry a dominant allele.
* Carrier status: Females can be carriers of a recessive sex-linked trait, meaning they have one copy of the recessive allele but do not express the trait themselves.
Examples of sex-linked traits include:
* Red-green color blindness
* Hemophilia
* Duchenne muscular dystrophy
