Forensic DNA Testing: RFLP Testing And PCR Testing
How many terms have we heard of criminal investigators conducting Forensic DNA Testing to find out who did the crime? To the cases that I have seen, conducting a Forensic DNA Testing allows the investigating agency to narrow down on the suspect in the case with considerable ease. Users of Forensic DNA Testing results have advocated that usage of results from such tests must not be used as a conclusive piece of evidence to zero in on the suspect. But in most cases, the DNA Test results point you in the right direction. Forensic DNA Testing is done by two ways - RFLP Testing and PCR Testing. Both the methods has its own list of advantages and disadvantages. Test surveys conducted of the forensic laboratories tell me that the PCR method is fast replacing the RFLP Testing method. Let us look at the factors that cause forensic laboratories to choose PCR Testing over RFLP Testing : · PCR Based testing requires less DNA samples than the RFLP Based testing. This helps forensic laboratories in cases where they are not able to collect large samples of DNA. · In cases of RFLP Testing, the DNA sample may be degraded partially. That means that the DNA Test can not be carried effectively as for a DNA Test to be done properly, a good sample of DNA is required. · PCR Based testing is extremely helpful for forensic scientists to zero in on evidence even in cases where the crime or the event site is heavily contaminated. PCR Bases tests allow magnification of the DNA samples to almost billion times more than their actual concentration, though extreme care is taken to ensure that these DNA samples are handled sensitively and carefully.
While the RFLP Based testing involves four discrete stages, PCR based testing accomplishes the test in a faster manner with the help of primers which are short pieces of DNA. The fact that PCR results alone can not be used for typing makes it a bit limited but fairly accurate and efficient tool for DNA Analysis. Results out of PCR based test magnifies the DNA sample than what you would have normally got when you would have an RFLP Test. This magnification helps the forensic scientists to do the DNA typing. Forensic DNA Testing is fast catching popularity to be used in a variety of circumstances. As is, this kind of testing is used to identify the criminals from a list of suspects who committed the crime, to identify the missing people in an air crash or a ship drowning incident. Virtually, I can see this list growing by the day as forensic laboratories are conducting research experiments to expand the uses of a Forensic DNA Testing. |
