Polymerase chain reaction(PCR) is a technique that mimics the DNA replication process and utilizes two basic molecular processes: 1-Complimentary DNA strand hybridization  2-DNA strand synthesis by Taq polymerase.  PCR exponentially amplifies a trace amount of DNA fragment for analysis and has many medical applications such as genetic testing(diagnostic test), tissue typing and study of cancer cells. For example, in order to determine the genetic nature of a virus spreading through a population, the PCR is first performed in different DNA samples fromvarious viruses and electrphoresis provides a clear fingerprint of each sample for comparison. 

 

The goal of the experiment was to determine the number of times the Alu sequence(located in non-coding region of PV92 gene) is repeated in the genome of two different humans. Alu sequence is inserted randomely into introns and has different frequency of repetition for different individuals. Analysis of Alu repeats can be used to estimate the frequency of this random insert in a population as a measure of molecular genetic variation. The DNA sample was extracted from cheek cells. First, the mouth rinse was centrifuged and the pellet which are cheek cells were obtained. The supernatant was drained and the resuspended solution of cheek cells were mixed with InstaGene matrix and exposed to 56C water bath for 10mins to inactivate DNases that can destroy the DNA. Next, in order to lyse the cell, the sample tube was exposed to 100C water bath for 5mins. The tube was then centrifuged and the supernatant was mixed with MasterMix solution which contains all the biomaterials necessary for PCR.