A trait that is expressed only when both alleles are recessive is called?

A trait that is expressed only when both alleles are recessive is called?

• A. Dominant Gene
• B. X-linked Gene
• C. Recessive Gene
• D. Codominant Gene

Answer: (C)

Traits are determined by pairs of alleles. If a trait appears only when both alleles are recessive, the dominant allele masks it whenever a dominant is present. That means the recessive allele must be paired with another recessive allele to be expressed, which is exactly what a recessive gene describes. The other terms don’t fit this pattern: a dominant gene produces the trait with at least one dominant allele, an X-linked gene refers to location on the X chromosome, and codominant means both alleles contribute to the phenotype.

Traits are determined by pairs of alleles. If a trait appears only when both alleles are recessive, the dominant allele masks it whenever a dominant is present. That means the recessive allele must be paired with another recessive allele to be expressed, which is exactly what a recessive gene describes. The other terms don’t fit this pattern: a dominant gene produces the trait with at least one dominant allele, an X-linked gene refers to location on the X chromosome, and codominant means both alleles contribute to the phenotype.