To identify which copy exhibits a deletion in the first codon triplet and then a substitution mutation, we first need to analyze the original DNA sequence and understand the changes represented by each response.
Original DNA segment: CCC ATA GCT
We break it into codon triplets:
- First codon: CCC
- Second codon: ATA
- Third codon: GCT
Now, we need to assess each response:
-
CCA ATA GCT:
- Change: CCC → CCA (substitution)
- No deletion in the first codon.
-
CCA TAG CT:
- Change: CCC → CCA (substitution) and deletion of both the second codon (ATA) and the third codon (GCT).
- Deletion occurred, but this appears to go beyond just a deletion in the first codon.
-
CCA TAA CT:
- Change: CCC → CCA (substitution) and deletion of the third codon (GCT).
- Again, this does not reflect just a deletion in the first codon.
-
CCC TAG CT:
- Change: None in the first codon (remains CCC), but the second codon has changed from ATA to TAG (substitution).
- No deletion has occurred.
Given these analyses, none of the options provided seem to meet the criteria of having a deletion only in the first codon triplet followed by a substitution mutation.
If a deletion was to occur only in the first codon, we would expect something like CC_ATA GCT (removal of one base) and then a substitution. However, since this isn't provided, it seems all examples deviate from your specific request.
If I had to infer, the response that most closely matches a simple change in the first codon with a substitution might be CCA ATA GCT, but it doesn't fit the criteria of containing both a deletion and a substitution as defined.
Please confirm the requirements or provide clarifications if specific answers are indeed required!