Polymerase chain reaction (PCR) is a method for amplifying a selected DNA sequence without cloning. It involves denaturing the DNA, annealing primers to the single-stranded DNA, and extending the primers via chain reaction. PCR has advantages over cloning in that it is more sensitive and faster, allowing for the study of scarce DNA amounts. Applications of PCR include comparing normal and mutant genes, detecting low-abundance sequences, forensic analysis, and prenatal diagnosis. Multiplex PCR simultaneously amplifies multiple regions using multiple primer pairs, such as detecting exon loss in large genes like CFTR.

1. POLYMERASE CHAIN
REACTION
BY: AIMEN HAIDER
IRHA JAMSHED

2. INTRODUCTION
DEFINITION
“ It is a test tube method for amplifying a selected
DNA sequence that does not rely on the
biological cloning method.”

3. STEPS OF A POLYMERASE
CHAIN REACTION
 Primer construction
 Denature the DNA
 Annealing of primers to single-stranded
DNA
 Chain extension

6. ADVANTAGES OF PCR
Advantage over cloning – sensitivity and speed
Sensitivity :
DNA sequence present in an individual cell ;
scarce amounts can be studied.
Speed :
DNA is very fast and technically less difficult
than traditional cloning methods using
recombinant DNA techniques.

7. APPLICATIONS
PCR has become a very common tool for a large
number of applications
1)Comparison of a normal gene with a mutant form of
the gene.
2)Detection of low-abundance nucleic acid sequences.
3)Forensic analysis of DNA samples.
4)Prenatal diagnosis and carrier detection of cystic
fibrosis.

9. Multiplex PCR
Definition :
“ The simultaneous amplification of multiple
regions of a target DNA using multiple primer
pairs is known as multiplex PCR. It allows
detection of the loss of 1 or more exons in a
gene with many exons.”
Example : gene for CFTR which has 27 genes