Which one of the following symbols and its representation, used in human pedigree analysis is correct?

Options

A.
B.
C.
D.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Pedigree Analysis**:
- In pedigree analysis, specific symbols are used to represent individuals and their relationships.

2. **Identifying Symbols**:
- A square (□) represents a male.
- A circle (○) represents a female.
- A shaded square (☐) indicates an affected male.
- A shaded circle (●) indicates an affected female.
- A diamond (♦) represents an unspecified sex.
- A shaded diamond (♦) indicates an affected unspecified sex.

3. **Understanding Relationships**:
- A single line connecting a male and female indicates mating outside of relatives.
- Two horizontal lines connecting a male and female indicate mating between relatives.

4. **Evaluating the Options**:
- **Option 1**: Affected male is represented by a shaded square. This is correct.
- **Option 2**: Mating between relatives is represented by two horizontal lines. This is correct.
- **Option 3**: Affected male is represented by a shaded square, but it is stated incorrectly. This is incorrect.
- **Option 4**: Unaffected male is represented by an unshaded square, and unaffected female is represented by an unshaded circle. This is correct.

5. **Conclusion**:
- The correct answer is **Option 2**, which represents mating between relatives.