Point mutation is

Options

A. loss of gene
B. change in a base of gene
C. addition of a gene
D. deletion of a segment of gene

Answer

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

1. **Definition of Point Mutation**: Point mutation is a type of mutation that occurs in the DNA or RNA of an organism's genetic material. It involves a change in a single nucleotide base.

2. **Types of Changes in Point Mutation**: In point mutations, a single nucleotide can undergo one of three types of changes:
- It can be **added** (insertion).
- It can be **deleted** (deletion).
- It can be **changed** (substitution).

3. **Specificity of Point Mutation**: The term "point mutation" specifically refers to the alteration of a single nucleotide base. This means that only one base is affected, even though multiple point mutations can occur in a single strand of DNA or RNA.

4. **Analyzing the Options**:
- **Option 1: Loss of gene** - This is incorrect as point mutation does not involve the complete loss of a gene.
- **Option 2: Change in a base of gene** - This is correct since point mutation specifically involves a change in a single nucleotide base.
- **Option 3: Addition of a gene** - This is incorrect as point mutation does not involve the addition of an entire gene.
- **Option 4: Addition of a segment of gene** - This is also incorrect as point mutation does not involve the addition of larger segments.

5. **Conclusion**: The correct answer to the question "Point mutation is" is **Option 2: Change in a base of gene**.

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