chromosomes with genes abcdefg becoming abedcfg is :

Options

A. duplication
B. deletion
C. translocation
D. inversion

Answer

To solve the question regarding the change in the chromosome sequence from ABCDEFG to ABEDCFG, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Original and Mutated Sequences**:
- Original sequence: ABCDEFG
- Mutated sequence: ABEDCFG

2. **Compare the Two Sequences**:
- Look at the positions of the genes in both sequences:
- A (1st position) remains A
- B (2nd position) remains B
- C (3rd position) is replaced by E (4th position in the original)
- D (4th position) is replaced by C (3rd position in the original)
- E (5th position) remains E
- F (6th position) remains F
- G (7th position) remains G

3. **Analyze the Changes**:
- The genes A, B, E, F, and G are in the same positions in both sequences.
- The genes C and D have swapped places, indicating a rearrangement.

4. **Determine the Type of Mutation**:
- The rearrangement of the sequence where two genes have switched places (C and D) is characteristic of an inversion mutation.
- Inversion occurs when a segment of a chromosome is reversed end to end.

5. **Conclusion**:
- The change from ABCDEFG to ABEDCFG is an example of an inversion mutation.

### Final Answer:
The correct answer is **inversion**.

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