After purifying a tiny sample of DNA, it is critical to determine its contents. To get a better picture of the DNA sequence, scientists can rapidly increase the number of copies of DNA. This challenge can be accomplished in the laboratory setting by using a little machine known as a thermocycler, free nucleotides, primers, and Taq polymerase in as little as a few steps:
To start the process of increasing the number of copies of the purified DNA, the following are added to a PCR tube:
Once the PCR tube is ready, the following steps are carried out:
Set the thermocycler settings to the specifications.
Insert the samples into the holder of the thermocycler.
Start the run cycle
Once the machine starts, the samples are put through several cycles. The first step is known as denaturation:
During denaturation, the machine heats the samples to break the bonds that hold DNA strands together, causing the two strands to separate. Once this occurs, the next stage, known as annealing, occurs. The temperature of the samples is lowered, allowing the free nucleotides to bind to the template strand.
Once the primers are attached to the template strand, the extension stage can begin:
The Taq polymerase can take the free nucleotides and elongate the strand during the extension stage. This process is repeated, starting with denaturation.
After each complete cycle, the amount of DNA increases. Large amounts of copies of DNA can be created in a relatively short period with a high degree of accuracy. PCR has many applications in the study of genomes and law.
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