If the above normal gene sequence changes to ABCABCDEFGH, then has occurred.

Options

A. deletion
B. point mutation
C. inversion
D. duplication

Answer

To solve the question regarding the change in the gene sequence to ABCABCDEFGH, we will analyze the situation step by step.

### Step-by-Step Solution:

1. **Identify the Original Sequence**:
- The original gene sequence is not explicitly provided, but we can infer that it is a sequence that, when altered, results in the new sequence ABCABCDEFGH.

2. **Analyze the New Sequence**:
- The new sequence is ABCABCDEFGH. Notice that the sequence "ABC" appears twice in succession at the beginning of the new sequence.

3. **Determine the Type of Change**:
- The repetition of the "ABC" segment indicates that there is an additional copy of this segment in the new sequence. This suggests that a mutation has occurred.

4. **Define Duplication**:
- In genetics, duplication refers to a mutation that involves the copying of a segment of DNA, resulting in the presence of two copies of that segment. In this case, the segment "ABC" has been duplicated.

5. **Conclusion**:
- Since the sequence has changed due to the repetition of the "ABC" segment, we conclude that the type of mutation that has occurred is **duplication**.

### Final Answer:
The change in the gene sequence to ABCABCDEFGH indicates that **duplication** has occurred.

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