Nucleic acid amplification technique
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Nucleic acid amplification techniques (NAAT) are biochemistry and molecular biology methods that involve the in-vitro synthesis of many copies of DNA or RNA from one original template.[1]
Types of Nucleic Acid Amplification Techniques (NAAT)
Ligase chain reaction
A ligase chain reaction is a DNA amplification technique based upon the ligation of oligonucleotide probes. The probes are designed to exactly match two adjacent sequences of a specific target DNA. The chain reaction is repeated in three steps in the presence of excess probe:
- Heat denaturation of double-stranded DNA
- Annealing of probes to target DNA
- Joining of the probes by thermostable DNA ligase
After the reaction is repeated for 20-30 cycles, the production of ligated probe is measured.[2]
Polymerase chain reaction
Polymerase chain reaction (PCR) is an in vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include:
- Thermal denaturation of the double-stranded target molecules
- Annealing of the primers to their complementary sequences
- Extension of the annealed primers by enzymatic synthesis with DNA polymerase
The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.[3]
Self-sustained sequence replication
Self-sustained sequence replication is an isothermal in-vitro nucleotide amplification process. The process involves the concomitant action of an RNA-directed DNA polymerase, ribonuclease(s), and DNA-directed RNA polymerases to synthesize large quantities of sequence-specific RNA and DNA molecules.[4]
References
- ↑ Anonymous (2024), Nucleic acid amplification technique (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Anonymous (2024), Ligase chain reaction (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Anonymous (2024), Polymerase chain reaction (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Anonymous (2024), Self-sustained sequence replication (English). Medical Subject Headings. U.S. National Library of Medicine.