If a part of gene is totally missing, it is called

Options

A. insertion
B. inversion
C. substitution
D. deletion

Answer

To solve the question "If a part of gene is totally missing, it is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking for the term used to describe a situation where a part of a gene is completely absent.

2. **Analyze the Options**: The options provided are:
- Insertion
- Inversion
- Substitution
- Deletion

3. **Define Each Term**:
- **Insertion**: This refers to the addition of one or more nucleotide base pairs into a DNA sequence. This does not relate to a missing part.
- **Inversion**: This involves a segment of DNA being flipped in orientation within the chromosome. This also does not indicate a missing part.
- **Substitution**: This is a mutation where one base pair is replaced by another. This means a part is changed, but not missing.
- **Deletion**: This is the process where a part of the gene is completely removed or absent.

4. **Identify the Correct Answer**: Since the question specifically asks for a situation where a part of a gene is totally missing, the correct answer is **Deletion**.

5. **Conclusion**: Therefore, if a part of a gene is totally missing, it is called **Deletion**.