Directions: The table lists the hair color and genotype of six individuals where black hair is dominant over blond. Use the table to answer any questions that follow. HAIR COLOR Name Hair color Alleles Mr. Johnson black homozygous Mrs. Johnson blond homozygous Mr. Valdez blond heterozygous Mrs. Valdez black heterozygous Mr. Ellwood black heterozygous Mrs. Ellwood blond homozygous If Mr. and Mrs. Johnson had four children together, what color of hair would the children likely have? a All 4 of the children would have black hair. b Only 3 of the children would have black hair, and 1 child would have blond hair. c All 4 of the children would have blond hair. d Only 2 of the children would have black hair, and 2 of the children would have blond hair.

Question

GPT-4o mini · Answer

To determine the likely hair color of the children of Mr. and Mrs. Johnson, we need to analyze their genotypes.

Mr. Johnson has black hair and is homozygous, which means his genotype is BB (both alleles for black hair). Mrs. Johnson is homozygous for blond hair, so her genotype is bb (both alleles for blond hair).

When Mr. Johnson (BB) and Mrs. Johnson (bb) have children, all the children will inherit one allele from each parent. The possible combinations of alleles from each parent are as follows:

From Mr. Johnson (BB), the only possible allele they can pass on is B (since he only has black alleles).
From Mrs. Johnson (bb), the only possible allele they can pass on is b (since she only has blond alleles).

Therefore, all offspring will have the genotype Bb.

Since black hair (B) is dominant over blond hair (b), all four children will have black hair.

The correct answer is: a. All 4 of the children would have black hair.