Everything You Need To Know About PCR Tests
Over the last two years, we have all become overly familiar with PCR tests and what they do. However, you may be shocked to learn that PCR testing kits have existed since long before the emergence of COVID-19.
As well as testing for variants of COVID-19, PCR tests can be used to test for many organisms, like viruses, in our bodies.
In today’s article, we are going to talk you through the history of PCR tests and the four key characteristics of a PCR.
The History Of PCR
PCR means polymerase chain reaction. PCR tests were developed to allow scientists to test for foreign organisms in a person’s body. It became such a successful tool for testing for COVID-19 because they have high success rates of detecting viruses.
It was first developed in 1983 by Kary Mullis. Mullis was later awarded the Nobel Prize for inventing the polymerase chain reaction testing system.
PCR is used for many different things – but is most commonly used for cloning DNA and for detecting diseases and pathogens.
The PCR is an expensive and quick biological technique that allows scientists to select a section of DNA and copy it billions of times if needed.
Doing this allows scientists to develop advanced DNA polymerases and to study how enzymes and DNA work. It can also be used to detect foreign organisms.
How To Take A PCR Test
When you do a PCR test, you are required to collect your own DNA (via a nasal or throat swab) and then this DNA is sent over to a lab to undergo PCR testing.
You will find everything you need to take the test in your PCR kit.
You will need to make sure that your hands are clean and that you have a sterile swab.
You will then need to rub the swab against the back of your throat and then on the inside of your nose. When this is done, put the swab into a clean container and seal it.
It will remain sealed until it reaches the lab and the scientists start the tests.
Characteristics Of PRC
There are 4 main characteristics of the PRC (polymerase chain reaction):
- Specificity
- Thermostability
- Fidelity
- Processivity
Specificity
For PCR to be beneficial to scientists they need to have a good deal of control over the part of the strand of DNA that they are trying to copy.
When PCR was first invented, it struggled with nonspecific amplification -experiments would have to be done completely until the right DNA was copied.
The increase in PCR specificity over the previous decade has allowed PCR to become even more useful than it already was. It is now more accurate than it has ever been.
Thermostability
For PCR to be successful, the enzymes and the DNA need to be heated up to a high temperature – the heat will cause the denaturing of the key enzymes and activate the DNA polymerase.
PCR enzymes need to be able to survive at higher temperatures than the DNA they are being used to study. Therefore, the more thermostable the PCR enzyme, the better it will function and the more variants of DNA it can be used on.
This is something scientists are still working on improving.
Fidelity
Fidelity is the word used to refer to how accurately scientists can read the results of a PRC test.
The importance of this is pretty self-explanatory, but that doesn’t make it any less vital to the success of the process.
High-fidelity DNA polymerases are enzymes that are easier for scientists to proofread and understand – they have lower rates of error and are able to more accurately replicate DNA sequences.
You cannot accurately compare the fidelity of a DNA polymerase unless the two enzymes have been through the same number of PCR cycles and the amplification rate is the same. This is because the more cycles and higher the amplification rate, the more likely errors are to appear.
Processivity
The final key characteristic of the PRC is processivity.
The processivity of an enzyme is defined as the number of nucleotides being processed in a single binding event.
Highly processive DNA polymerase fared better when used in long and complex PCR tests.
A PRC enzyme needs to score well in all four characteristics if it is to be successful. It must be able to lock onto specific sequences, survive high temperatures, be easily proofread, and be highly processive.
