Method to detect GM food - PCR

The most common type of method to detect GM food is PCR - Polymerase Chain Reaction
The Polymerase Chain Reaction is an in vitro technique used to enzymatically amplify a specific DNA region that lies between two regions of known DNA sequence.
Even a single gene copy can be amplified to a million copies within a few hours using PCR.

There are 3 steps in PCR:
-First, the target genetic material must be denatured, the strands of its helix must be unwound and separately by heating to 90 - 96*C.
-The hybridization or annealing where the primers bind to their complementary bases on the now single stranded DNA
-Then the extension of the DNA chain by nucleotide addition from the primers using DNA polymerase as catalyst in the presence of Mg2+.