Question

7/7
Two brown eyed parents (Bb) have a baby. What is the chance the baby is blue eyed?
0%
75%
25%
50%

Answer 1

To determine the chance that a baby will have blue eyes from two brown-eyed parents with the genotype Bb (where B represents the brown eye allele and b represents the blue eye allele), we can use a Punnett square.

Each parent has the following possible allele combinations:
- Parent 1: B (brown) or b (blue)
- Parent 2: B (brown) or b (blue)

The possible combinations for the offspring are:
1. BB (brown eyes)
2. Bb (brown eyes)
3. bB (brown eyes)
4. bb (blue eyes)

From this, we can see that there is 1 bb combination out of 4 total combinations. Therefore, the probability of having a baby with blue eyes (bb) is:

\[
\text{Probability} = \frac{\text{Number of blue-eyed combinations}}{\text{Total combinations}} = \frac{1}{4} = 25\%
\]

So, the chance that the baby is blue-eyed is **25%**.