Question

In humans, brown eyes are dominant over blue eyes. Assume that eye color in this case is the result of alleles of a single gene. A person with brown eyes and a person with blue eyes have children. Which of the following possible outcomes (sets of children) would allow the brown-eyed person to determine their genotype with certainty?

a. All brown-eyed children.

b. Having 1 brown-eyed child.

c. Having four blue-eyed children.

d. Having 2 brown-eyed and 2 blue-eyed children.

Answer 1

The correct answer is option a. In humans, brown eyes are dominant over blue eyes. The brown-eyed person can determine their genotype with certainty when all the children have brown eyes.

Step-by-step explanation:

In humans, eye color is determined by multiple genes. Assuming that eye color is determined by a single gene in this case, the brown-eye color is dominant over blue-eye color. When a person with brown eyes and a person with blue eyes have children, the possible outcomes are as follows:

1. All brown-eyed children: If all the children have brown eyes, then the brown-eyed person can determine their genotype as homozygous dominant (BB).
2. Having 1 brown-eyed child: If one child has brown eyes and the rest have blue eyes, then the brown-eyed person can determine their genotype as heterozygous (Bb).
3. Having four blue-eyed children: If all the children have blue eyes, then the brown-eyed person can determine their genotype as homozygous recessive (bb).
4. Having 2 brown-eyed and 2 blue-eyed children: If there is an equal number of brown-eyed and blue-eyed children, it is not possible for the brown-eyed person to determine their genotype with certainty as they could be either heterozygous (Bb) or homozygous recessive (bb).

Therefore, the correct option is a. All brown-eyed children, as it allows the brown-eyed person to determine their genotype with certainty.