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Uses for the PCR technique?

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Uses for the PCR technique?

Postby Z0rr0 » Mon May 04, 2009 7:46 am

Hello. I have to list three uses for the PCR technique. One has to fall under forensic science, one has to fall under medicine, and one has to fall under scientific research.

I'm struggling with some, but I am making an effort. Would these reasons be alright to list?

Forensic Science: Making copies of the same DNA sample enables testing the DNA sample under different conditions. For example, if a piece of skin is found at a crime scene and another piece of skin is found at a different location, the skin samples can be replicated and tested to see if the skin samples share identical results when being tested. This enables the original samples to not be destroyed after one test.

Medicine: The PCR technique enables early diagnosis of malignant diseases.

Scientific Research: Um, not sure what to write here.

Could someone help me please?
Last edited by Z0rr0 on Mon May 04, 2009 7:58 am, edited 1 time in total.
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Postby Z0rr0 » Mon May 04, 2009 7:49 am

Hmmm, I'm thinking of saying that a gene could be replicated numerous times and exposed to different viruses to see if the gene is naturally immune to any. But I'm not sure if that can go anywhere. >.<
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Re: Uses for the PCR technique?

Postby Swordy » Mon May 04, 2009 5:33 pm

you probably have the right idea for some of these but based on how you described it, it looks like your thinking PCR is something else so let me help you out here :)

Highly simplified and leaving out lots of technical info, Picture DNA as a big book... PCR is a Photocopier that lets you make scientific notations amounts of copys of a few pages... based on how you described the Forensic use you made it seem like your making multiple copies of the piece of skin….plus they don’t do forensic testing like that anymore due to the low success rate :P

For Forensic,
Using DNA sequencing and Microsatellite Variance tests it is possible to determine if two skin samples at different crime scenes belong to the same person and their DNA can be tested against a Data Base of criminals to find out who it is, or if that comes back negative when a potential suspect is caught their DNA can be tested against the skin samples to see if they were at the crime scene.. (if you want to seem really smart mention the Forensic DNA evidence is only considered circumstantial evidence in a Court of Law)

Your mostly right though a more fun one would have been for testing for genetic diseases such as Alzheimer’s and Dementia 
There’s a lot of different ones here but the one I am best familiar with is using PCR to copy Microsatellites in different animals of the same species to determine if they are related as well as what animals would be good to mate together to prevent inbreeding in captive animal populations… you could also go with using PCR to unlock which DNA sequences do stuff in the cell but you would have to research that as I can’t help you with that sorry…

That help you out?

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Postby canalon » Mon May 04, 2009 5:35 pm

Your first answer is slightly inaccurate, but the basic idea is correct. I suggest you read a little bit more about the use of DNA in forensic. Here for example:
http://www.ornl.gov/sci/techresources/H ... sics.shtml

Second answer: Malignant diseases? But infectious diseases. or genetic diseases would be correct.

Third situation: I feel generous, and I am working on this technique so read about that:

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
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Postby MrMistery » Mon May 04, 2009 11:41 pm

another very elegant and extremely widely used scientific application is site-directed mutagenesis, commonly referred to as quickchange pcr, probably after some early commercial form of the protocol.
Wikipedia has a nice explanation of the technique:

For plasmid manipulations, this technique has largely been supplanted by a PCR-like technique where a pair of complementary mutagenic primers is used to amplify the entire plasmid. This generates a nicked, circular DNA which can undergo repair by endogenous bacterial machinery. However, this process does not amplify the DNA exponentially, rather, linearly. Yields are complicated by the fact that the product DNA must undergo the nick repair and is not supercoiled, resulting in lowered efficiency of transformation in bacteria. Finally, the product DNA is of the same size as the plasmid. Therefore, the template DNA must be eliminated by enzymatic digestion with a restriction enzyme specific for methylated DNA. The template, which for this technique should be biosynthesized will be digested, but the mutated plasmid is preserved because it was generated in vitro and is therefore unmethylated.
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