If a trait is X-linked recessive,who would express the trait?
A)homozygous dominant females and hemizygous recessive males
B)heterozygous recessive females and hemizygous dominant males
C)homozygous recessive females and hemizygous recessive males
D)heterozygous dominant females and hemizygous dominant males
E)the same proportions of females and males

Question

Quizplus · Accepted Answer

Since the trait is X-linked recessive, it means the gene responsible for it is located on the X chromosome. Females have two X chromosomes, and males have one X chromosome and one Y chromosome. For a female to express the recessive trait, she would need to inherit two copies of the recessive allele (one from each parent). Therefore, homozygous recessive females (CC) would express the trait. For a male to express the recessive trait, he only needs to inherit one copy of the recessive allele since he has only one X chromosome. Therefore, hemizygous recessive males (C) would express the trait. Heterozygous dominant females (Cc) and hemizygous dominant males (C) would not express the trait, and homozygous dominant females (CC) would not even carry the recessive allele. The proportion of females and males expressing the trait would depend on the frequency of carriers in the population and the likelihood of the recessive allele being expressed in males due to their hemizygosity.

If a Trait Is X-Linked Recessive,who Would Express the Trait