Nucleic acid hybridization means joining two complementary DNA by hydrogen bonds to form a double-stranded molecule. The basic principle of DNA microarray is nucleic acid hybridization. Microarray helps in analyzing large amounts of samples. With this advanced technique, gene function can be studied through expression measurements of a genome.
Microarray analysis can be divided into two main steps:
- Probe production
- Target production (cDNA)
Specific sequences are immobilized to a surface and react with labeled complementary DNA (cDNA) targets. A signal resulting from the hybridization of the labeled target with the specific probe will identify which RNA is present in the unknown target sample.
Below is an example of the procedure:
- Sample collection: Two samples of healthy as well as infected tissue for comparison are preferred.
- Isolate mRNA from the collected sample using the column or solvent method.
- Probes are fixed to solid substrates (glass or chips).
- Prepare labeled cDNA from the isolated RNAs. Labeling is done by using fluorescent dyes like Cy3 and Cy5.
- Place prepared and labeled cDNAs into the DNA chips/microarray trays with the required probe for hybridization.
- When complementary DNA from specimens is added, it will bind to probes in the array.
- Reporter probes attach to the hybridized sequences and usually fluoresce giving a positive signal indicating the presence of the sequence in the array.
22. Raza, Khalid. "Analysis of Microarray Data using Artificial Intelligence Based Techniques." Handbook of Research on Computational Intelligence Applications in Bioinformatics, 2016, Chapter 11, pages 216–239. Publisher: IGI Global. DOI: 10.4018/978-1-5225-0427-6.ch011.
