PCR (polymerase chain reaction) uses DNA to denature into single strand at 95℃ in vitro. At low temperature (often about 60℃), primers and single strand are combined according to the principle of base complementary pairing, and then the temperature is adjusted to the optimal reaction temperature of DNA polymerase (about 72℃), and DNA polymerase synthesizes complementary strand along the direction from phosphoric acid to pentose (5'-3'). The PCR instrument based on polymerase is actually a temperature control device, which can well control denaturation temperature, renaturation temperature and extension temperature.

Knowledge expansion:

Polymerase chain reaction (PCR) is a molecular biology technique for amplifying specific DNA fragments, which can be regarded as a special DNA replication in vitro. The biggest feature of PCR is that it can greatly increase a small amount of DNA. Therefore, as long as a little DNA can be isolated, it can be amplified and compared by PCR, whether it is fossils, the remains of historical figures, or the hair, skin or blood left by the murderer in a murder case decades ago.

This is also the power of "trace evidence". This idea was first put forward by Mullis in the United States in 1983, and the simple DNA amplification method was invented by Mullis in 1985, which means the real birth of PCR technology. Up to now, 20 13, PCR has developed to the third generation technology. From 65438 to 0973, Taiwan Province scientist Qian Jiayun discovered the stable Taq DNA polymerase, which also made a fundamental contribution to the development of PCR technology.

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DNA "transforms" into a synthetic chemistry platform-technology-People's Network?