Basic Rules of Primer Design

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Basic Rules of Primer Design

    1. Make sure that the primers are not self-complementary or complementary to the other primer in the reaction mixture, as this will encourage the formation of hairpins and primer-dimers and will compete with the template for the use of primer and reagents.
    2. If possible, make the 3′ end terminate in C or A, as the 3′ is the end which extends and neither the C nor A nucleotide wobbles (unconventional base pairings in RNA molecule that does not conform to traditional Watson-Crick base pairing). This will increases the specificity. Mispriming can be avoided by making the 3′ end slightly AT rich. Again, there are software tools to help design these, such as AutoDimer, available on the National Institutes of Standards and Technology (NIST) website at: http://www.cstl.nist.gov/strbase/AutoDimerHomepage/AutoDimerProgramHomepage.htm. Accessed November 26, 2018.
    3. The concentration of each individual primer should be lower than in singleplex reactions, because the cumulative primer concentration in the reaction can become too high. Concentrations greater than 1 µM can cause primers to anneal along non-target regions which will result in the generation of false product. Insufficient concentrations of either primer could result in little or no amplification. In addition, primer pairs for internal controls should be much less than those for the targets.

Hairpin primers: When two regions of the same strand,
usually complementary in nucleotide, form a double helix
that ends in an unpaired loop.