Question

By which process miss-incorporated base can change into a permanent mutation?

• A. Replication
• B. Transcription
• C. Translation
• D. Transposition

Hint:

During DNA replication, errors can be introduced that may result in permanent mutations if not corrected by repair mechanisms.

Answer 1

The Correct Option is A

Step 1: Understanding mutation process.
A miss-incorporated base in DNA can cause a permanent mutation if it is replicated and passed on to daughter cells. This occurs during the replication process, where incorrect base pairing is not corrected.
Step 2: Analyzing the options.
(1) Replication: Correct — During DNA replication, if a base is incorrectly incorporated and not repaired, it can lead to a permanent mutation.
(2) Transcription: Incorrect, transcription is the process of synthesizing RNA from DNA, not where permanent mutations occur.
(3) Translation: Incorrect, translation is the process of protein synthesis, not directly related to permanent mutations in DNA.
(4) Transposition: Incorrect, transposition refers to the movement of genetic elements within the genome but doesn't typically result in permanent mutations from miss-incorporated bases.
Step 3: Conclusion.
The process by which a miss-incorporated base becomes a permanent mutation is (1) Replication.

Answer 2

A DNA replication error only becomes a permanent, heritable mutation once it has been "fixed" into the genome. Let's check each process against this requirement.

1. Replication: When a mismatched base escapes proofreading and mismatch repair during DNA replication, it becomes a permanent part of the DNA sequence, and after another round of replication, this altered base is copied into subsequent generations of DNA, fixing it as a heritable mutation.
2. Transcription: Transcription copies DNA into RNA, but any errors introduced here affect only that particular RNA transcript and are not passed on to daughter DNA molecules, so they are not permanent.
3. Translation: Translation converts RNA into protein, and errors at this stage affect only the protein product, with no effect on the DNA sequence itself.
4. Transposition: Transposition involves the movement of genetic elements to new locations in the genome, which is a different process from fixing a miss-incorporated base as a point mutation.

Only replication converts a transient miss-incorporated base into a permanent, heritable change in the DNA sequence.

Therefore, the correct answer is Replication.