A heterozygous father suffers from an autosomal dominant trait. Which of these statements is true ?

Options

A. All sons will suffer from the disease while the daughters will not suffer from the disease
B. All daughters will suffer from the disease while the sone will not suffer from the disease
C. None of his children will suffer from the disease
D. Some of his children may suffer from the disease

Answer

To solve the question regarding a heterozygous father suffering from an autosomal dominant trait, we can follow these steps:

### Step 1: Understand the Genetics of Autosomal Dominant Traits
- An autosomal dominant trait means that only one copy of the dominant allele is needed for an individual to express the trait.
- If the father is heterozygous (I i), he has one dominant allele (I) and one recessive allele (i).

### Step 2: Determine Possible Genotypes of Offspring
- The father (I i) can pass on either the dominant allele (I) or the recessive allele (i) to his children.
- The mother’s genotype is assumed to be homozygous recessive (ii) since the question does not specify that she has the trait.

### Step 3: Create a Punnett Square
- Set up a Punnett square to visualize the possible combinations of alleles from the father and mother:

| | i | i |
|-------|-----|-----|
| **I** | I i | I i |
| **i** | i i | i i |

### Step 4: Analyze the Offspring Genotypes
- From the Punnett square, we can see that:
- 50% of the offspring (I i) will inherit the dominant allele and express the trait.
- 50% of the offspring (i i) will inherit the recessive alleles and not express the trait.

### Step 5: Conclusion
- Therefore, some of the children (50%) may suffer from the disease, while others (50%) will not.
- The correct statement is: "Some of his children may suffer from the disease."

### Final Answer
The true statement is: **Some of his children may suffer from the disease.**

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