Which term describes an allele whose effects are not observed in a heterozygous individual?

Which term describes an allele whose effects are not observed in a heterozygous individual?

• A. Recessive Trait/Allele
• B. Dominant Trait/Allele
• C. Codominant
• D. Incomplete Dominance

Answer: (A)

In diploid organisms, alleles can be dominant or recessive. A recessive allele is one whose effects are masked when a dominant allele is present in the same individual. In a heterozygous genotype, the phenotype is determined by the dominant allele, so the recessive trait isn’t seen unless the organism has two copies of that recessive allele. That’s why the term described is recessive. By contrast, a dominant allele is expressed even when only one copy is present, and codominance or incomplete dominance describe cases where both alleles influence the phenotype in the heterozygote.

In diploid organisms, alleles can be dominant or recessive. A recessive allele is one whose effects are masked when a dominant allele is present in the same individual. In a heterozygous genotype, the phenotype is determined by the dominant allele, so the recessive trait isn’t seen unless the organism has two copies of that recessive allele. That’s why the term described is recessive. By contrast, a dominant allele is expressed even when only one copy is present, and codominance or incomplete dominance describe cases where both alleles influence the phenotype in the heterozygote.