PCR Instrument

Denaturation: The PCR instrument initially heats the DNA sample to a high temperature, typically around 95°C, which causes the double-stranded DNA to separate or denature into two single strands.

Annealing: After denaturation, the temperature is lowered to around 50-65°C, allowing primers (short DNA sequences) to bind or anneal to their complementary sequences on each single DNA strand. The primers serve as starting points for DNA replication.

Extension: The temperature is raised to around 72°C, and a DNA polymerase enzyme is added to the reaction mixture. The enzyme extends the primers by adding complementary nucleotides to each single DNA strand. This process results in the synthesis of new DNA strands that are complementary to the original template strands.

These three steps (denaturation, annealing, and extension) constitute one cycle. PCR instruments can run multiple cycles, typically ranging from 20 to 40 cycles, amplifying the specific DNA target exponentially with each cycle.By controlling the temperature precisely and cycling through these steps rapidly, PCR instruments facilitate the amplification of even a small amount of DNA or RNA into millions to billions of copies, enabling various applications such as genetic testing, diagnostics, genotyping, cloning, and DNA sequencing.