How can PCR primers be used to mutate DNA?
PCR stands for polymerase chain reaction. It’s a technique used to rapidly make many copies of a short fragment of DNA. PCR works by repeatedly heating and cooling a DNA sample. When it’s heated, the two DNA strands separate. An enzyme called polymerase can then synthesize new strands of DNA on each individual strand, producing two new double stranded fragments. The cycle is repeated several more times, each time doubling the number of DNA fragments. To mark the beginning and end of the region that needs to be copied, a very short DNA fragment of about 20 nucleotides is needed as starting point for the enzyme. These short fragments are called “primers”. The primers need to match the region of the DNA at the start and end of the region to be copied, so they can bind at the correct spot. However, primers can still bind if one nucleotide is changed, or mutated. If you carry out PCR with primers containing a mutation, the resultant DNA copies will also contain this mutation. These copied a
