An allele that is hidden when the dominant allele is present is called which term?

• A. Dominant allele
• B. Recessive allele
• C. Carrier allele
• D. Mutant allele

Answer: (B)

In genetics, the way alleles influence a trait depends on dominance. An allele is recessive when its effect is masked by a dominant allele in a heterozygous individual. So if one copy of the dominant allele and one copy of the recessive allele are present, the dominant trait shows up and the recessive allele’s effect is hidden. Only when two copies of the recessive allele are present does the recessive trait appear. That’s why the term for an allele that is hidden when a dominant allele is present is recessive. A carrier refers to someone who carries a recessive allele but may not express the trait, and a mutant allele denotes a different version of a gene that isn’t defined by masking alone.