Recessive Trait

1. Find the recessive allele. 2. Check whether both alleles are recessive. 3. If yes, the recessive trait appears. 4. If a dominant allele is present, the recessive trait stays hidden. 5. Write the phenotype clearly.

A 2 x 2 Punnett square helps show that recessive traits appear only when both alleles in a pair are recessive.

A common wrong answer is to say the recessive trait appears whenever it is present in the genotype. That is wrong because the dominant allele can hide it.

A recessive trait is the trait that appears only when both alleles are recessive.

A recessive trait is the trait that appears only when both alleles are recessive. A recessive trait is expressed only in homozygous recessive condition and is masked by a dominant allele in heterozygous condition. In pea plants, short stem height is recessive. A plant with genotype tt will be short, while Tt will still be tall if tallness is dominant.

A recessive trait stays hidden when a dominant allele is present. It becomes visible only in a homozygous recessive condition, such as tt in many textbook examples. This is why recessive traits may skip a generation and then appear again when the right combination is present. A recessive trait is expressed only in homozygous recessive condition and is masked by a dominant allele in heterozygous condition. If t stands for short stem and T stands for tall stem, then tt gives short plants. In Tt, the dominant tall allele hides the short trait, so shortness does not appear. Identify the visible trait in a recessive condition, or explain why a recessive trait may be hidden in a heterozygote. A common wrong answer is to say the recessive trait appears whenever it is present in the genotype. That is wrong because the dominant allele can hide it.