Non-sense mutation is seen in?
**Core Concept:**
Non-sense mutations are a type of genetic mutation that occur when a premature stop codon is introduced into the coding sequence of an mRNA molecule, leading to a truncated protein. This can result in a loss of protein function or a non-functional protein, which can lead to a genetic disorder.
**Why the Correct Answer is Right:**
A **non-sense mutation** (NM_000013.4:c.10T>C) refers to a specific genetic change in the human genome. In this case, the correct answer is **D** (premature stop codon), as it represents the molecular mechanism behind non-sense mutations. When a nucleotide change occurs in the coding region of a gene, it can lead to the incorporation of a premature stop codon. This premature stop codon (UAA, UAG, or UGA) interrupts the normal translation process, causing the production of a truncated protein that often lacks critical functional domains and is therefore non-functional or non-specific.
**Why Each Wrong Option is Incorrect:**
A. Premature stop codons (UAA, UAG, or UGA) are typically associated with nonsense mutations, not the specific nucleotide change represented by option A (premature stop codon).
B. This option refers to a frameshift mutation, which is a different type of genetic change that does not involve premature stop codons.
C. This option describes a missense mutation, which involves a single nucleotide change leading to an amino acid substitution, not the specific nucleotide change represented by option D (premature stop codon).
**Why Option D is Right:**
Non-sense mutations are characterized by the production of truncated proteins, which are often nonfunctional or non-specific. The specific nucleotide change represented by option D (premature stop codon) is a crucial aspect of understanding the molecular mechanism behind non-sense mutations, making it the correct answer.
**Core Concept:**
Genetic mutations can occur in various regions of a gene, including the coding region where premature stop codons can lead to non-sense mutations.
**Why Each Wrong Option is Incorrect:**
A. Missense mutations involve a change in the amino acid sequence, as explained in option C (missense mutation).
B. Frameshift mutations occur when a change in the DNA sequence causes a shift in the reading frame, leading to a different amino acid sequence, not the specific nucleotide change represented by option D (premature stop codon).
C. Deletions or insertions of nucleotides can lead to frameshift mutations, which is different from the specific nucleotide change represented by option D (premature stop codon).