Question

magine you are trying to determine the phenotypic ratio of hair color. Brown (B) hair color is the dominant trait and blonde (b) hair color is the recessive trait. What is the phenotypic ratio if one parent is heterozygous and the other parent is homozygous recessive for this trait? Group of answer choices 3:1 (brown:blonde) 3:1 (blonde:brown) 1:1 (brown:blonde)

Answer 1

Answer:

1:1 (brown:blonde)

Explanation:

Brown hair color (B) is dominant over blonde hair color (b).

Heterozygous parent will have the genotype Bb

Homozygous recessive parent will have the genotype bb.

Crossing hetezygous parent with homozygous recessive parent:

Bb   x   bb

Progeny: Bb, Bb, bb, and bb.

2 Bb brown hair

2 bb blonde hair

Phenotypic ratio = 1:1 (brown:blonde)

The correct answer is  1:1 (brown:blonde).