In the previous entry, we learned how a process invented to increase the size of research samples of DNA called polymerase chain reaction is used to test for viruses even though the guy who received a Nobel Prize for inventing it said using it that way doesn’t work.
Kary Mullis’s PCR process takes segments of DNA through a “cycle” that doubles the amount. If you run a single segment of DNA through just 40 cycles, you’ll end up with 1 x 240, which is over a trillion copies. Remember that number, it’s going to be important later.
We also saw that the COVID-19 virus, like any other virus, is just some genetic code surrounded by a shell that acts as a “Trojan horse,” allowing the virus to invade the cells of living organisms. Once inside, the genetic code exits the shell, hijacking the cell’s functions to make it produce more copies of the virus.
The genetic code inside the COVID-19 virus’s shell is RNA. So, since the PCR cycle only works on DNA, before a sample is tested for COVID-19 another process is used to convert the former into the latter. Once that’s done, the sample is run through a number of PCR cycles to amplify the amount of any converted-viral-RNA that was originally in it so there’s enough be detected.