One of the issues that scientists commonly encounter when they are processing a DNA test is that they don’t have much sample to work with. In essence, scientists are given just a few strands of DNA to work with, which can prove challenging when trying to obtain a sample. The main problem here is that sometimes, more abundant DNA is required for testing purposes to produce accurate results. Chances are, a scientist is going to be looking for thousands, if not millions, of different chains of the DNA in question so that they can continuously run tests on to produce results. However, how can this be achieved where only a small sample is obtainable?

By using a method called polymerase chain reaction (PCR), scientists can take a single copy of a piece of DNA and multiply it consistently until they have millions, if not more, copies of the DNA piece to work with. The name comes from the key component in the amplification of DNA. DNA polymerase is an enzyme that assists in the replication of DNA. They catalyze (speed up) the polymerization of deoxyribonucleotides alongside the DNA strand. These polymerases read the code and then use it as a template. By using it as a template, they are able to make another strand and then another strand, to create the required quantity of material for examination.

DNA Testing – Development of the PCR technique

The PCR technique was developed in 1983 by Karry Mullis. Karry Mullis, an American biochemist, won the Nobel Prize for the creation of PCR in 1993, and it has since become a central technique in biochemistry and molecular biology. However, the story behind its invention is rather interesting. The inspiration for PCR came from road markings, which its creator noted when riding his Scooter. The concept of using a pair of primers as a bracket came to mind and he realized that it would allow for the sequence that was desired to be made, thus PCR as a technique was born.

DNA Testing – Key application of PCR

One particular field of science that relies heavily on PCR is DNA forensics. If hair was left at a crime scene that was not that of the victim, scientists would have little material to work with. If they want to run one of the many different types of DNA testing, they will naturally require more DNA to analyze. Therefore, by running a polymerase chain reaction, they can replicate more of the DNA for testing purposes. By doing this, they can ensure that they have enough to continuously run DNA tests, with a view to providing more accurate results.

The creation of the polymerase chain reaction was a defining improvement to molecular biology and biochemistry. At one time, scientists were only able to use very little amounts of the desired DNA chain, yet now they are able to replicate the sequence they desire and continuously create more and more material for testing purposes, which is of particular relevance in forensic testing of genetic material or in determining whether an accused individual may in fact be guilty of the alleged crime.