A sequence of nucleotides on DNA 'CATCATCATCAT' is changed through mutation to 'CAATCATCATCAT'. What is this type of mutation called?

Options

A. Nonsense
B. transition, transition, transversion, transversion respectively
C. Transversion
D. Frame shift

Answer

To determine the type of mutation that has occurred in the DNA sequence from 'CATCATCATCAT' to 'CAATCATCATCAT', we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Original and Mutated Sequences**:
- Original Sequence: CATCATCATCAT
- Mutated Sequence: CAATCATCATCAT

2. **Locate the Change**:
- Compare the two sequences. The first three nucleotides in the original sequence are 'CAT', while in the mutated sequence, they are 'CAA'. The difference is the addition of an extra 'A' in the mutated sequence.

3. **Determine the Type of Mutation**:
- The addition of an extra nucleotide (A) in the sequence indicates that a base has been inserted. This type of mutation is known as an **insertion mutation**.

4. **Analyze the Impact on the Reading Frame**:
- Since the insertion of an additional nucleotide alters the grouping of the subsequent nucleotides into codons, it leads to a change in the reading frame. This is referred to as a **frameshift mutation**.

5. **Conclusion**:
- Therefore, the type of mutation that has occurred is classified as a **frameshift mutation** due to the insertion of a nucleotide that changes the reading frame of the sequence.

### Final Answer:
The type of mutation is called a **frameshift mutation**.

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