Thanks for listening to the third episode of Emily Vs. Science! In this episode I discuss PCR (polymerase chain reaction) testing as it relates to COVID-19. This semester many colleges and universities are implementing a COVID-19 testing system to keep students safe on campus. As I mentioned in the podcast, the Illinois Return-to-campus plan was first introduced back in Fall 2020 and now lots of campuses like UW Madison have implemented the same system this semester (Spring 2021).

I know that the PCR test is hard to understand, so here is the Kahn Academy explanation that helped me understand it quite a bit. More so, here is the Cleveland Clinic’s contribution to how they use the PCR to test for COVID-19.

Finally, here are the links to the history of PCR, as supplied by ThermoFisher Scientific and the

Kary Mullis Nobel Prize speech to further the understanding of how the PCR test came to be.

Steps of PCR Testing:

Denaturation:heating up the DNA + Taq polymerase enzyme reaction to denature or separate the DNA strands from it’s double helix form
Annealing: cooling down the sample so the primers can attach to where they have been told to attach (based on what the experimenter is looking for)
Extension: heating up the reaction again so the Taq polymerase enzyme can stnthesize new DNA stands

This process repeated 25-35 times and creates millions to billions of copies of the selected portion of DNA

Here’s a graphic from the National Human Genome Research Institute that shows the three steps of a PCR test to solidify the concept.