Wife is PTC non-taster and husband is PTC taster. Their son is taster but daughters are non-tasters. This is not a sex linked trait. Which pedigree is correct ?

Options

A.
B.
C.
D.

Answer

To solve the question regarding the inheritance of PTC tasting ability in the family described, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Traits**:
- The wife is a PTC non-taster (homozygous recessive, let's denote this as "tt").
- The husband is a PTC taster (could be homozygous dominant "TT" or heterozygous "Tt").

2. **Determine the Genotype of the Children**:
- The son is a taster, which means he is either "TT" or "Tt".
- The daughters are non-tasters, which means they must be "tt".

3. **Analyze the Possible Genotypes**:
- Since the daughters are non-tasters (tt), the father must be heterozygous (Tt). If he were homozygous dominant (TT), all children would be tasters.
- Therefore, the husband’s genotype is "Tt".

4. **Construct the Pedigree**:
- The pedigree starts with the husband (Tt) and wife (tt).
- The son (Tt) inherits the taster trait from the father and the non-taster trait from the mother.
- The daughters (tt) inherit the non-taster trait from both parents.

5. **Draw the Pedigree**:
- The husband (Tt) is represented as a filled square (affected).
- The wife (tt) is represented as an unfilled circle (unaffected).
- The son (Tt) is represented as a filled circle (affected).
- The daughters (tt) are represented as unfilled circles (unaffected).

6. **Select the Correct Pedigree**:
- Compare the constructed pedigree with the options provided. The correct pedigree will show the husband as affected, the wife as unaffected, the son as affected, and the daughters as unaffected.

### Conclusion:
The correct pedigree is option A, as it matches the described inheritance pattern.

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