To analyze the provided DNA segment (CCC ATA GCT) and determine which response exhibits a deletion in the first codon triplet (CCC) followed by a substitution mutation, let's break this down step by step.
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Original DNA sequence: CCC ATA GCT
- Codon triplets: CCC | ATA | GCT
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Deletion in the first codon triplet: This means we need to remove one or more bases from "CCC". If we delete one base, we could lose any one of the "C" bases:
- Possible deletion scenarios:
- C removed: CC ATA GCT
- C removed: C C A ATA GCT
- C removed: CC C ATA GCT
However, the most likely deletion for simplicity would be the last C, resulting in "CC" instead of "CCC".
- Possible deletion scenarios:
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Substitution mutation: After identifying the first codon as CC, we now consider what substitution might occur next.
Now let’s look through the provided options to identify which one has these changes:
- CCC TAG CT — No deletion or substitution present.
- CCC TAG CT — No deletion or substitution present.
- CCA TAG CT — Indicates a deletion of one "C" (leaving CC) followed by a substitution of the last "C" to "A" (CCA).
- CCA TAG CT — Again indicates a deletion of one "C" and a substitution.
- CCA ATA GCT — Similar deletion and substitution as above; however, it replaces the second codon.
- CCA ATA GCT — Same as above, indicating a deletion and substitution on the second triplet.
- CCA TAA CT — This option features a deletion and a substitution, but it’s unclear which ones exactly correlate with our initial assessment.
Best Match: The most appropriate answer based on the mutation pattern (deletion in the first codon and a substitution) is:
CCA TAG CT
This indicates the deletion of one 'C' from "CCC" to form "CC" and then substitutes the last 'C' in that triplet with an 'A' to form "CCA".