A sex linked trait can be defined by which genotypes. Choose all which apply.

a. Coded for on the X and Y chromosomes

b. Coded for on the X but not Y chromosome

c. Coded for on the Y but not X chromosom

d. a dominant allele on any chromosome

a. Coded for on the X and Y chromosomes

b. Coded for on the X but not Y chromosome

c. Coded for on the Y but not X chromosome

Explanation:

The X and Y chromosomes are the sex chromosomes as they are involved in sex determination. All the genes that are present on the X and Y chromosomes are inherited along with these chromosomes and therefore, exhibit sex-linked inheritance.

X and Y chromosomes share a homologous region. Therefore, the sex-linked genes are defined as the ones present on both X and Y chromosomes as well as the ones that are present on either X or Y chromosomes.

For example, the gene for hemophilia is present on the X chromosome; but not on the Y chromosome. The SRY gene is present only on the Y chromosome.