Question

Genetics Problem: Mom is heterozygous for brown eyes, and Dad has blue eyes. What is the percent chance that a child will have blue eyes? Brown eyes? (p. 483 )

Short answer

Answer: The probability of their child having blue eyes is 50% and the probability of their child having brown eyes is 50%.

Step-by-step solution

Understanding eye color inheritance

Eye color is determined by the presence or absence of the dominant brown eye color gene (B) and the recessive blue eye color gene (b). A person can have two copies of the brown eye gene (BB), two copies of the blue eye gene (bb), or one of each (Bb). A person with at least one brown eye gene (BB or Bb) will have brown eyes, while a person with two blue eye genes (bb) will have blue eyes.

Determine the parents' genotypes

In this problem, Mom is heterozygous for brown eyes, which means she has one brown eye gene and one blue eye gene (Bb). Dad has blue eyes, which means he has two blue eye genes (bb).

Creating a Punnett square

A Punnett square can help us visualize the possible genetic makeup of their offspring by considering all possible combinations of the parents' genes. In this case, we have a simple 2x2 Punnett square. | | B | b | |---|-----|-----| | b | Bb | bb | | b | Bb | bb |

Calculating probabilities for eye color

Looking at the Punnett square, we can determine the probabilities for each genotype and corresponding eye color: 1. Bb (Brown eyes): - There are 2 Bb combinations out of 4 total possibilities. - Probability of having brown eyes: (2/4) * 100 = 50% 2. bb (Blue eyes): - There are 2 bb combinations out of 4 total possibilities. - Probability of having blue eyes: (2/4) * 100 = 50% Therefore, there is a 50% chance that a child will have blue eyes and a 50% chance that a child will have brown eyes.