If genotype Aa, which phenotype is expressed?

If genotype Aa, which phenotype is expressed?

• A. Recessive phenotype.
• B. Dominant phenotype.
• C. Mixed phenotype.
• D. No phenotype.

Answer: (B)

When a genotype is Aa, there is one dominant allele and one recessive allele. In a simple dominant-recessive pattern, the dominant allele is expressed even when a recessive allele is present, so the phenotype shown is the dominant trait. For example, if A codes for tall and a codes for short, Aa individuals appear tall. The recessive phenotype would only appear if both alleles were recessive (aa). A mixed or intermediate phenotype would require incomplete dominance or codominance, which isn’t the case here. No phenotype isn’t correct because the gene is expressed and the dominant trait is visible.

When a genotype is Aa, there is one dominant allele and one recessive allele. In a simple dominant-recessive pattern, the dominant allele is expressed even when a recessive allele is present, so the phenotype shown is the dominant trait. For example, if A codes for tall and a codes for short, Aa individuals appear tall. The recessive phenotype would only appear if both alleles were recessive (aa). A mixed or intermediate phenotype would require incomplete dominance or codominance, which isn’t the case here. No phenotype isn’t correct because the gene is expressed and the dominant trait is visible.