Which statement correctly describes incomplete dominance?

Which statement correctly describes incomplete dominance?

• A. One allele fully masks the other in heterozygotes.
• B. There is complete dominance.
• C. Heterozygotes show both phenotypes separately.
• D. Heterozygotes show an intermediate phenotype.

Answer: (D)

Incomplete dominance means neither allele is fully dominant, so the heterozygote shows a blend of the two traits rather than the trait of one allele masking the other. The classic example is red and white flowers producing pink offspring in the heterozygote, showing an intermediate phenotype rather than red or white itself. This is why the statement describing heterozygotes as having an intermediate phenotype fits incomplete dominance best. The other ideas describe different patterns: one allele fully masking the other is complete dominance; heterozygotes showing both phenotypes is codominance where both traits are expressed distinctly.

Incomplete dominance means neither allele is fully dominant, so the heterozygote shows a blend of the two traits rather than the trait of one allele masking the other. The classic example is red and white flowers producing pink offspring in the heterozygote, showing an intermediate phenotype rather than red or white itself. This is why the statement describing heterozygotes as having an intermediate phenotype fits incomplete dominance best.

The other ideas describe different patterns: one allele fully masking the other is complete dominance; heterozygotes showing both phenotypes is codominance where both traits are expressed distinctly.