Change in number of chromosome is called

Options

A. Chromosomal aberration
B. Aneuploidy
C. Both A and B
D. None

Answer

**Step-by-Step Solution:**

1. **Understanding Chromosomes**: Chromosomes are structures within cells that contain DNA and are responsible for carrying genetic information. Each organism has a specific number of chromosomes that is characteristic of its species.

2. **Definition of Change in Chromosome Number**: When there is a change in the number of chromosomes, it can lead to various genetic conditions. This change can either be an increase or a decrease in the normal chromosome number.

3. **Terminology**: The condition where there is a change in the number of chromosomes is referred to as "Chromosomal aberration." This term encompasses various types of chromosomal changes, including structural changes and numerical changes.

4. **Aneuploidy**: A specific type of chromosomal aberration is called "Aneuploidy." This term is used when there is an abnormal number of chromosomes, such as having one extra chromosome or one less chromosome than the normal count.

5. **Examples of Aneuploidy**:
- **Down Syndrome**: This condition is caused by the presence of an extra chromosome 21 (total of 3 instead of 2).
- **Klinefelter Syndrome**: This syndrome occurs in males who have an extra X chromosome (XXY instead of XY).
- **Turner Syndrome**: This condition occurs in females who have only one X chromosome (X0 instead of XX).

6. **Conclusion**: Therefore, the change in the number of chromosomes is referred to as "Chromosomal aberration," and a specific type of this change is called "Aneuploidy."

**Final Answer**: The change in the number of chromosomes is called Chromosomal aberration or Aneuploidy.

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