What is required for an offspring to express a simple recessive trait?

What is required for an offspring to express a simple recessive trait?

• A. A single dominant allele
• B. Two dominant alleles
• C. Recessive alleles from both parents
• D. One recessive and one dominant allele

Answer: (C)

For an offspring to express a simple recessive trait, it must inherit recessive alleles from both parents. This is because recessive traits only manifest in the phenotype when both alleles for that trait are recessive. In a situation where a dominant allele is present (whether in a heterozygous state with one dominant and one recessive allele, or in a homozygous state with two dominant alleles), the dominant trait will overshadow the recessive one, resulting in the dominant phenotype being expressed. Therefore, both alleles must be recessive for the offspring to display the recessive characteristic, making the inheritance of recessive alleles from each parent essential for the expression of that trait.

For an offspring to express a simple recessive trait, it must inherit recessive alleles from both parents. This is because recessive traits only manifest in the phenotype when both alleles for that trait are recessive. In a situation where a dominant allele is present (whether in a heterozygous state with one dominant and one recessive allele, or in a homozygous state with two dominant alleles), the dominant trait will overshadow the recessive one, resulting in the dominant phenotype being expressed. Therefore, both alleles must be recessive for the offspring to display the recessive characteristic, making the inheritance of recessive alleles from each parent essential for the expression of that trait.