In man brown eye is dominant over blue. A lady with brown eyes, whose father was blue eyed is married to a man with blue eyes. What percentage of her progeny will be blue eyed

Options

A. 0
B. 0.25
C. 1
D. 0.5

Explanation

To solve the problem, we need to determine the genotypes of the individuals involved and then perform a Punnett square analysis to find the percentage of progeny with blue eyes.

### Step-by-Step Solution:

1. **Identify the Genotypes**:
- The lady has brown eyes (B) but her father had blue eyes (b). Since blue is recessive, this means the lady must be heterozygous (Bb) for eye color.
- The man has blue eyes, which means he must be homozygous recessive (bb).

2. **Set Up the Cross**:
- We will cross the genotypes of the lady (Bb) and the man (bb).
- The gametes from the lady can be B (brown) or b (blue).
- The gametes from the man can only be b (blue).

3. **Punnett Square**:
- Create a Punnett square to visualize the genetic combinations:
```
| b | b |
-----------------
B | Bb | Bb |
-----------------
b | bb | bb |
```
- From the Punnett square, we can see the possible genotypes of the offspring.

4. **Determine the Offspring Phenotypes**:
- The offspring genotypes are:
- Bb (brown eyes) - 2 occurrences
- bb (blue eyes) - 2 occurrences
- Therefore, the phenotypes of the offspring will be:
- Brown eyes (Bb): 2
- Blue eyes (bb): 2

5. **Calculate the Percentage of Blue-Eyed Progeny**:
- Total offspring = 4
- Blue-eyed offspring = 2
- Percentage of blue-eyed progeny = (Number of blue-eyed offspring / Total offspring) × 100
- Percentage = (2/4) × 100 = 50%

### Final Answer:
50% of the progeny will have blue eyes.

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