The allele expressed in the heterozygous condition that masks the recessive allele is called

• A. Allele
• B. Carrier
• C. Chromosome
• D. Dominant

Answer: (D)

In genetics, when two different alleles are present in a person, one can mask the other in the phenotype. The allele that does the masking is called the dominant allele, and it determines the trait you see in the organism. The recessive allele is only expressed when two copies are present (homozygous recessive). A carrier describes someone who has a recessive allele but does not express the trait, which is a different concept from the allele that governs the visible trait. A chromosome is the structure that carries genes, not a term for how an allele is expressed. An allele is simply a variant of a gene, not necessarily about dominance.