This is an example of which type of mutation?
First, I need to figure out what the question is really asking. Since the options are empty, perhaps the original question was about a specific mutation type, like point mutation, frameshift, nonsense, etc. Let me assume the correct answer is a nonsense mutation. That's a common one in genetics questions.
Now, the core concept would be about mutation types and their effects on DNA. The explanation should cover how different mutations alter the DNA sequence and their consequences. For the correct answer, I'll explain that a nonsense mutation creates a premature stop codon, leading to a truncated protein.
For the wrong options, if the options were, say, silent, missense, frameshift, I need to explain why they're incorrect. Silent doesn't change the amino acid, missense changes to a different amino acid, frameshift shifts the reading frame.
The clinical pearl could be about the severity of nonsense mutations causing non-functional proteins. Finally, the correct answer line would be the letter and answer text.
I need to make sure all sections are included and follow the formatting rules. Keep each section concise, use bold for key terms, and stay within the character limit. Let me check the example response to see the structure again. Okay, I think that's covered. Let me put it all together now.
**Core Concept**
Mutations are classified based on their effect on DNA sequence and protein function. **Nonsense mutations** introduce a premature stop codon, truncating the protein and often causing loss of function. This is distinct from silent, missense, or frameshift mutations, which alter codons differently.
**Why the Correct Answer is Right**
A **nonsense mutation** occurs when a single nucleotide change converts a codon into a stop signal (e.g., CAG → UAG). This results in a shortened, nonfunctional protein due to premature termination of translation. For example, in **β-thalassemia**, nonsense mutations in the β-globin gene reduce hemoglobin production.
**Why Each Wrong Option is Incorrect**
**Option A:** *Silent mutations* do not alter the amino acid sequence due to codon redundancy (e.g., GAA → GAG for glutamic acid).
**Option B:** *Missense mutations* replace one amino acid with another (e.g., GAG → GTG in sickle cell anemia), altering protein function.
**Option C:** *Frameshift mutations* result from insertions/deletions not divisible by three, shifting the reading frame and causing multiple amino acid changes.
**Clinical Pearl / High-Yield Fact**
Nonsense mutations are clinically significant because they often cause severe diseases (e.g., cystic fibrosis, Duchenne muscular dystrophy) by producing truncated, nonfunctional proteins. Remember: **“Stop codons = protein truncation”** is a key exam point.
**Correct Answer: C. Nonsense Mutation**