PCR testing has been in the spotlight as the most reliable way of screening for COVID-19 in patients since the beginning of the pandemic. But what is PCR? And what are its other uses?
PCR stands for “polymerase chain reaction,” and it works by detecting, isolating, and amplifying the DNA sequence of a specific virus by exponentially replicating it. PCR was invented by American biochemist Kary Mullis in 1985 while working at biotechnology company Cetus, following an epiphany he had while driving—an achievement that earned him the Nobel Prize in Chemistry in 1993.
PCR’s amplification process enables it to detect small portions of genetic material from viruses like SARS-CoV-2, causing COVID-19. It can also be used for a broad range of other applications. Let’s explore five of those other—perhaps lesser-known—applications for PCR testing:
1. Agricultural Development
PCR is used at many stages of agricultural product development, including gene discovery, screening, and quality control. It is also helpful in detecting and quantifying the presence of genetically modified (GM) content in food—an important application given that many jurisdictions have imposed labeling requirements on the food industry.
DNA sequences can be compared using PCR testing in order to detect variations acting as biomarkers for certain inherited diseases and the risk of developing them. Obtaining this information enables physicians to make targeted lifestyle recommendations and design personalized courses of treatment. Genotyping is also used in rodents during research and drug development.
3. Vaccine Development
PCR has important uses in not only detecting viruses once they are present, but also in developing the vaccines used to protect against them. The PCR process is relevant to multiple stages of vaccine development, from the initial characterization of the viral genome to vaccine optimization.
4. Paternity Testing
There are several methods used to determine paternity, with DNA testing (like PCR) being the most reliable. Using a blood sample, scientists can employ PCR to amplify a very small amount of DNA to prepare it for testing. Accurate testing can even be performed prior to birth, because a very small amount of fetal DNA is present in a pregnant women’s blood—which is especially useful.
PCR was a gamechanger in the forensics field when it was first used in 1986 to exonerate a suspect who had falsely confessed to crimes. The first conviction obtained with the help of PCR testing occurred the following year. PCR’s amplification ability means that DNA fingerprinting can be performed using only small amounts of genetic material, making it suitable for a wide range of criminal investigations.
Following Mullis’s epiphany and two years of subsequent work performed by himself and his team, PCR has advanced virtually every field relying on DNA studies, including viral detection, agricultural development, genotyping, vaccine development, paternity testing, and forensics. Given its versatility and applicability to so many important areas, we can expect to see a growing range of uses that will yield even more benefits in the future.