A Polymerase Chain Reaction (PCR)

860 Words 4 Pages
A. Polymerase chain reaction (PCR)
Principle
It includes the primer mediated enzymatic amplification of DNA. It uses the ability of DNA polymerase to manufacture new strand of DNA complementary to the offered template strand. DNA polymerase can add a nucleotide only onto a preexisting 3′-OH group to add the first nucleotide that is way Primer is required. Then DNA polymerase elongates its three ends by adding more nucleotides to generate an extended region of double-stranded DNA.
Procedure
All the PCR components are mixed and are taken through series of 3 important cyclic reactions held in an automated, self-contained thermocycler machine.
Denaturation:
The double strand denature to single-stranded DNA
Annealing:
Binding of the primers
…show more content…
B. DNA Fingerprinting
Principle
The genome of human contains 3 billion base pairs, and they are organized in a specific sequence that gives us a unique identity. 90% of the DNA is same in all of us. DNA fingerprinting depend on the rest 10% difference in the human DNA. In DNA fingerprinting they match the uncommon sequence of humans with the suspect's unique sequence.
Procedure
• Obtaining a sample of DNA from the cells.
• Cutting the DNA at specific areas using special proteins which are called as restriction enzymes. This enzymes produces fragments of different lengths that are arranged by electrophoresis.
• Splitting of the sorted double-stranded DNA fragments to single strands and after that, they transport them to a nylon sheet.
• The fragments undergo autoradiography where they are revealed to DNA probes—pieces of synthetic DNA that are made radioactive.
• An X-ray film the fragments. When a radioactive probe attaches to the fragments, a dark mark will be displayed. This pattern of marks is analyzed.
Applications
• Used for the paternity

Related Documents