RFLPs are the oldest type of DNA finger prints. Fr this process, asample from any part of the body is collected since all the nucleated cells of the body contain DNA. Ater the sample is collected, DA is extracted from the sample by using restriction enzymes(Crocket 2001). Rstriction enzymes are highly specific enzymes for specific sequences of DNA and they act on and cleave only the sequences they are programmed for. After the DNA samples are properly extracted, secific band patterns are generated in agarose gel by using of Electrophoresis.
Tis is a process in which electric current is applied to each side of the sheet containing the extracted DNA on a sheet and movement of particles is observed which creates a band patter (Burke 1991). Tis band pattern is then recorded on a nylon sheet by placing it over the agarose gel containing the original pattern and RFLPs are obtained by probing them either with a fluorescent material or radioactive material. Te Second type of DNA finger print is VNTR. Tey appear as 9-80 base repeats regions of chromosomes.
Fr the purpose to generate DNA fingerprints of an individual in this type, fur steps are requiredAnother and the most modern and technologically advanced process for the purpose of generating DNA fingerprints is STR i. Sort Tandem Repeats and PCR i. Plymerase Chain Reaction. Tis technique has revolutionized the world of forensic sciences as generation of DNA fingerprints and identification process is much quicker and easier now. Tis technique generates smaller base repeats i. 25 that are easy to be analyzed by PCR. Te PCR is mainly for the purpose of amplification.
Fr this purpose three necessary things required are: 1 A priming sequence, 2 TAQ Polymerase and 3) a solution of 4 DNA bases (Burke 1991). Al these things are mixed in the test tube along with the sample to be analyzed and then they go through a cycle of three main steps i. Tis process completes in about 2 minutes. Te cycle is repeated again and again till the required amount of amplification is reached which is usually 50 cycles equivalent 25 times (Burke 1991).
S far, SR and PCR have been the most famous types of DNA fingerprints. A compared to the complicated process of generating fingerprints by using RFLP and VNTR, te process of STR and PCR is less complex and. ..
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