Numerical change in chromosome number which is not the exact multiple of haploid genome is

Options

A. Triploid
B. Allopolyploid
C. Autopolyploid
D. Aneuploid

Answer

To solve the question regarding the numerical change in chromosome number that is not an exact multiple of the haploid genome, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terminology**:
- The term "haploid" refers to a cell that has one complete set of chromosomes (n).
- The term "diploid" refers to a cell that has two complete sets of chromosomes (2n).

2. **Identify the Concept of Aneuploidy**:
- Aneuploidy is a condition where there is a numerical change in the chromosome number that is not an exact multiple of the haploid number (n). This means that the total number of chromosomes is either more than or less than the standard diploid number (2n) by a specific number of chromosomes.

3. **Differentiate Between Aneuploidy and Polyploidy**:
- It is important to distinguish between aneuploidy and polyploidy. Polyploidy involves a complete set of chromosomes being multiplied (e.g., triploid (3n), tetraploid (4n)), whereas aneuploidy does not follow this pattern.

4. **Conclusion**:
- Based on the definitions and understanding of aneuploidy, we can conclude that the numerical change in chromosome number that is not an exact multiple of the haploid genome is termed **"aneuploid."**

### Final Answer:
The numerical change in chromosome number which is not an exact multiple of the haploid genome is called **aneuploidy**.

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