Learning Objective: At the end of this lesson, the learner will be able to explain the principle and applications of DNA/RNA microarrays and understand their use in gene expression analysis, genotyping, and clinical diagnostics
Microarrays are laboratory tools that allow simultaneous analysis of thousands of genes in a single experiment. They can detect gene expression differences, single-nucleotide polymorphisms (SNPs), and copy number variants (CNVs).
Microarrays are commonly applied in:
- Gene expression profiling
- Clinical genetic testing
- Forensic analysis
- Cancer mutation detection
- Genetic linkage studies
Principle
- A solid surface (chip) is prepared with thousands of known DNA sequences (probes) fixed at specific locations.
- Labeled sample RNA or DNA is hybridized to the array.
- Complementary sequences bind to the probes.
- Fluorescence scanning detects which sequences have hybridized and the relative amount of bound sample.
Types of Microarrays
| Type | Analyte | Use |
|---|---|---|
| Expression microarray | RNA | Compares gene expression levels between two samples (e.g., healthy vs tumor tissue) |
| SNP/CNV array | DNA | Detects single-nucleotide polymorphisms or copy number variations for genotyping, mutation detection, and linkage analysis |
Clinical Applications
| Field | Application |
|---|---|
| Oncology | Detect tumor-specific gene expression patterns and mutations |
| Genetic testing | Identify disease-associated SNPs, CNVs, and hereditary disorders |
| Forensic analysis | DNA profiling for identification purposes |
| Research | Study differential gene expression under different conditions or treatments |
