Question

When two alleles of the same gene are identical, the individual carrying those alleles is said to be ____.

a) Heterozygous
b) Homozygous
c) Dominant
d) Recessive

Answer 1

An individual with two identical alleles for a gene is homozygous, which can be either homozygous dominant or homozygous recessive; the latter expresses a recessive trait while the former expresses a dominant trait.

Step-by-step explanation:

When two alleles of the same gene are identical, the individual carrying those alleles is said to be homozygous. This can occur in two forms: homozygous dominant, where both alleles are dominant (e.g., AA), or homozygous recessive, where both alleles are recessive (e.g., aa). The expression of alleles can be dominant or recessive, with the dominant gene masking the effect of a recessive gene when present. Therefore, a recessive trait will only be observed in individuals that are homozygous recessive, as homozygous dominant and heterozygous individuals will express the dominant trait.