Polymerase Chain Reaction - Essay Example

The paper 'Polymerase Chain Reaction' is a perfect example of genetics research.
The polymerase chain reaction was first invented by a Biochemist named Kary Mulis during the early 1980s. This process involves the resultant formation of an unlimited number of DNA replicates from the original single DNA molecule. All of the DNA replicates had similar characteristics to that of the original single molecule of DNA strand; identical genes. This process has tremendously improved and made it a less daunting task for the molecular biologists who attempt to make particular specific DNA strands from the original single molecule of DNAs. The process of polymerase chain reaction mainly relies on the DNA template, DNA polymerase, Primers, and nucleotides.

            The DNA molecule is mainly composed of two complementary strands of the polynucleotide chain surrounded by the outer sugar-phosphate backbone that entails the deoxyribose sugar units and the phosphate molecules. DNA has four different deoxynucleotides which are; deoxythyamine (T), deoxyadenylate (A), deoxycytidylate (C), and deoxyguanylate (G). The main function of these nucleotides is to encode the genetic information from the DNA. These deoxynucleotides link together with the aid of hydrogen bond linkages. For instance, adenine links with thymine with the two hydrogen bond linkages whereas the cytosine and the guanine link together using three hydrogen bond linkages. The double strands of DNA are anti-parallel thus forming a double helix DNA structure in which the strands are held together by weak hydrogen bonds. The structure of a DNA strand has one end termed as a chemical convention by which is usually exhibited as the 3’ ends while the other is the 5’. This is contrariwise and opposite to the other DNA strand thus contributing to the anti-parallel structure of the DNA strands.

DNA polymerase, which is an enzyme, is one of the vital components in the repair and replication of DNA. The enzyme is responsible for lengthening of a short oligonucleotide, which is also the primer by attaching an additional nucleotide to the 3’ end of the hybridized primer in the template strand of DNA. During this process, nucleotide triphosphate molecules, which are in solution form acts as the building block. The nucleotide by which the enzyme polymerase attaches to will be complementary to the nucleotide base located in the corresponding position on the template DNA strand. During this process, each strand serves as a template for the other in readiness for DNA replication.

The Polymerase Reaction Chain Experiment in the Laboratory

Objective: To determine the DNA sequence

Materials

1. Source of heat
2. DNA polymerase
3. DNA templates strands
4. DdNTP
5. Primers

Procedure

1. Heat the targeted DNA so as to separate the double helix complementary DNA strand into single DNA strands. This process is called DNA melting.
2. Hybridize an oligonucleotide (primer) to a complementary sequence on one of the strands.
3. Place small portions of the DNA mixture into four different test tubes each containing specific ddNTP which are radioactively labeled.
4. Add DNA polymerase enzyme that would lengthen the hybridized oligonucleotides in each tube due to the addition of a single ddNTP.
5. To separate the extended oligonucleotides from the residual deoxynucleotide, electrophoresis process is employed. This is by identifying which radioactively labeled ddNTP was introduced to the oligonucleotide.
6. Therefore, determine the corresponding complementary base in the target strand. Through being acknowledged of the identity of the ddNTP added to the primers, one is able to know the identity of the corresponding base which is the template strand. Thus, one is able to come up with the identity of a base in the template strand next to the site where the primers bind.

The polymerase reaction chain may be used as a technique in the laboratory in:

1. The DNA cloning of organisms such as human cloning
2. Helps in research on the diagnosis of hereditary diseases
3. Diagnosis of infectious diseases.
4. Used in the identification of genetic fingerprints used in forensic science