An allele that is only expressed when no dominant allele is present describes which term?

An allele that is only expressed when no dominant allele is present describes which term?

• A. Recessive
• B. Dominant
• C. Allele
• D. Genotype

Answer: (A)

Recessive is the term for an allele that only shows up in the phenotype when there is no dominant allele present. In genetics, a dominant allele masks the effect of the other allele in a heterozygous individual, so as long as at least one dominant copy is present, the dominant trait is expressed. The recessive trait appears only when the organism has two copies of the recessive allele (no dominant allele). The other terms describe different ideas: a dominant allele is the one that masks, an allele is simply a variant of a gene, and genotype refers to the specific pair of alleles an organism carries, not the trait that is expressed.

Recessive is the term for an allele that only shows up in the phenotype when there is no dominant allele present. In genetics, a dominant allele masks the effect of the other allele in a heterozygous individual, so as long as at least one dominant copy is present, the dominant trait is expressed. The recessive trait appears only when the organism has two copies of the recessive allele (no dominant allele). The other terms describe different ideas: a dominant allele is the one that masks, an allele is simply a variant of a gene, and genotype refers to the specific pair of alleles an organism carries, not the trait that is expressed.