**Question:** All the following can be used to detect the mutation, except

A. **Whole genome sequencing (WGS)**
B. **Whole exome sequencing (WES)**
C. **Sanger sequencing**
D. **Methylation analysis**

**Correct Answer: D. Methylation analysis**

**Core Concept:**
Mutation detection refers to the process of identifying alterations in an individual's DNA sequence. There are various molecular techniques used for this purpose. Whole genome sequencing (WGS), whole exome sequencing (WES), and Sanger sequencing are examples of DNA sequencing methods, while methylation analysis assesses the chemical modification of DNA molecules.

**Why the Correct Answer is Right:**
Methylation analysis is not a direct method for detecting mutations in DNA sequences. Instead, it measures the addition of a chemical group called a methyl group to the DNA molecule, which can have epigenetic effects on gene expression without altering the DNA sequence. Methylation analysis is primarily used to study the epigenetic modifications rather than identifying mutations.

**Why Each Wrong Option is Incorrect:**
A. **Whole genome sequencing (WGS)**: WGS involves sequencing the entire genome to identify single nucleotide polymorphisms, insertions, deletions, and structural variations. It is a powerful tool for detecting mutations.

B. **Whole exome sequencing (WES)**: WES focuses on sequencing the coding regions (exons) of the genome, which accounts for around 1-2% of the genome. It is also useful for detecting mutations, particularly those affecting protein-coding regions.

C. **Sanger sequencing**: Sanger sequencing, also known as dideoxy sequencing, is a method for determining DNA sequences. It is a widely used technique in molecular biology research and clinical diagnostics for mutation detection.

**Clinical Pearl:**
Understanding the difference between these techniques is crucial for selecting the appropriate method for detecting genetic mutations depending on the research question or clinical scenario. For example, if studying rare mutations or whole exome sequencing, WES is suitable; if studying protein-coding regions, Sanger sequencing is preferred; and for epigenetics, methylation analysis is relevant. Whole genome sequencing (WGS) and whole exome sequencing (WES) are powerful tools for detecting genetic mutations, while Sanger sequencing is a widely used technique for DNA sequencing.