The scientists already know the DNA sequence of a HIV virus based on which they develop the primers called HIV primers. Now during the PCR they mix the DNA sample of the person with this HIV primer (along with enzyme and nucleotides), and if this sequence matches with the target (patient's) DNA there will be amplification which means that the person is infected. And if the sequence doesn't match then there will not be any amplification which means that the person is not infected. If this right what are the roles of PCR in detecting unknown diseases?
Hi there,
If you want to perform PCR diagnosis, you need a minimal knowledge of the disease to design primers...
PCR is an amplification tool, it will enhance the number of amplicons or desired genes in the reaction which u can analyze further as well in details. No matter the quantity of genome of any pathogen in your original sample, PCR will simply amplify this number high enough for diagnosis and for further assessments...as now you have pretty high number of genes in your reaction cuvette. So even trace amount of genetic material in your sample which you cannot analyze by any molecular technique can be amplified by the PCR....and that is the theme....And by using specific set of primers for a pathogen sequence you can detect the presence of that pathogen in your samples.
It's interesting to see the idea of how you can use PCR to detect the samples infected with HIV. I really don't know the answer for this question but it made me think about the DNA testing using PCR to see if the kid belongs to the father.
Without PCR it is very difficult to detect unknown diseases. After getting the sequence we usually go for the BLAST, it shows us about the identity say 90% or so. But if it is not showing any identity, then our work starts.
For unknown diseases we usually go for the universal primers.
If we are talking about viruses, there are other techniques also like ELISA and electron microscopy, through which you can identify the organism or else you can get the clue what to do next.
All the best !!!
Ashish
Well, with the PCR you can amplify the targeted region and then if you sequence the sample you may get the variations to the reference genes. These variations includes insertion/deletions (indels) and single nucleotide polymorphisms (SNPs). Further to that you need to link these to a symptoms that the patient has like the cancer patient.
It is not an easy way to do it but it can be done.
Many thanks for all! May I couldn't ask the question in the right way. Of course, no one can ignore the important role of PCR for amplification of the target gene or target sequence of DNA, yes, it's just an amplification tool. So, I want to know if this tool has a role in detecting of unknown diseases or not especially the viral diseases. Of course one can use the enzyme-linked immunosorbent assay (ELISA) to detect the presence or amount of a target protein, but on DNA level after determination its sequences for many pathogens why we didn't use PCR in detecting on the pathogen but how?
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