If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is

Options

A. autosomal dominant
B. autosomal recessive
C. sex-linked dominant
D. sex-linked recessive

Explanation

To solve the question, we need to analyze the genetic inheritance pattern described. Here’s the step-by-step solution:

### Step 1: Understand the scenario
The question states that a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny. This indicates that the mother does not express the disease herself but carries the allele responsible for it.

**Hint:** Identify the key characteristics of the mother (carrier but normal) and the affected offspring (only males).

### Step 2: Identify the type of inheritance
Since the disease is passed on from a female to male offspring, and only some of the males are affected, it suggests that the disease is linked to the sex chromosomes. Specifically, it implies that the disease is likely recessive and linked to the X chromosome.

**Hint:** Consider how traits are passed through sex chromosomes, especially focusing on X-linked inheritance.

### Step 3: Determine the nature of the disease
In X-linked recessive inheritance, males (XY) will express the disease if they inherit the affected X chromosome from their mother. Females (XX) can be carriers if they have one affected X and one normal X. Therefore, a carrier female can pass the affected X chromosome to some of her sons, resulting in those sons expressing the disease.

**Hint:** Recall that males have only one X chromosome, so if they inherit the affected X, they will show the disease.

### Step 4: Provide an example
A classic example of an X-linked recessive disease is hemophilia. In this condition, a carrier mother can have affected sons, while her daughters would either be carriers or unaffected, depending on whether they inherit the affected X chromosome.

**Hint:** Think of well-known genetic diseases that follow this pattern to reinforce your understanding.

### Conclusion
Based on the analysis, the genetic disease in question is an X-linked recessive disease.

**Final Answer:** The disease is X-linked recessive.