The evolving field of PCR: which method will you choose?

Sewing the first seeds on the road

In 1993, Kary B. Mullis was awarded the Nobel Prize in Chemistry “for his invention of the polymerase chain reaction (PCR) method” together with Michael Smith “for his fundamental contributions to the establishment of oligonucleotide-based, site-directed mutagenesis…”. The two methods synergistically contributed to the development of innovative procedures within DNA-based chemistry thus revolutionising the future of genetic engineering.

The intriguing story behind the invention of PCR is one of those classic examples of biological discoveries, with an initial idea sprouting, before becoming shaped and honed, and then finally, the culmination of full recognition by the scientific community. According to Kary B. Mullis, the revelation of the PCR process came to his mind during a three-hour moonlight drive in the Californian mountains, back in April 1983¹. That night, he realised that a pair of primers could be used to copy a specific target DNA using DNA polymerase and that by raising the temperature of the sample, the extended oligonucleotides could then be separated from the DNA targets thus becoming the templates for the next cycle in a chain reaction. The procedure could be repeated many times, doubling the amount of DNA target at each step. Through such iterative cycles, millions of copies of the desired DNA segment could be exponentially generated within a few hours¹.