A comprehensive description of multiple displacement amplification with mechanism of reaction catalyzed by phi-DNA polymerase .

1. By : Faizan Saleem

2. Introduction
 Multiple displacement amplification is a non-pcr based
amplification technique.
 It does not require multiple cycles for the amplification of
template DNA.
 An specific type of DNA polymerase is required i.e Φ29 DNA
polymerase.
 Even minute quantity of DNA from single cell can be amplified
with high fidelity rate.
 Whole amplification process requires a constant temperature of
30°C .

3. Φ29 DNA polymerase
 Φ29 DNA polymerase is obtained from bacteriophage Φ29.
 It has been extensively used in the field of molecular
biology.
 It comprises of two domains:
 A C-terminal domain (polymerase domain).
 An N-terminal domain (3'-5’ exonuclease domain).
 As compared to other type of polymerases, It has a higher
processitivity and proofreading ability.

4. How it Works:

6. Hyper Branched Structure

7. Pros and Cons

8. Pros :
 It provides higher processitivity , More than 70 kb of DNA
can be obtained.
 Higher fidelity rate, Φ29 DNA polymerase has a 3’–5'
proofreading activity that provides amplification error rate
to 1 in 106−107 bases compared to
conventional Taq polymerase.
 DNA from a single cell can be used for amplification.
 Does not require a thermo cycler .

9. Cons :
 Over amplification of a certain region may occur.
 Primer dimer formation is common occurrence.
 Allelic Dropout may occur in case of heterozygous sample.
 Requires constant temperature.

10. Applications of MDA
 Single cell genome sequencing.
 Forensic Analysis.
 SNP genotyping
 Southern Blotting etc.

11. Recent Work Done :