Primer Design
Trouble-shooting Primer Applications
Contact the Corelab director for help with primer design, programmatic design, blast searching and suitability for multiplexing. MIT's Primer3 is available on-line, or via EMBOSS using eprimer3.
More information on batch design and data processing methods is on our bioinformatics page.
Oligo Design Problems and Possible Solutions
| Performance Problem | Application | Design Remedy | Notes |
|---|---|---|---|
|
Background due to false priming in genomic or other DNA samples with much unknown sequence. |
PCR,Sequencing |
Select oligonucleotides with high specificiy. |
Determine stability (delta G) of the 3-prime ends of oligonucleotides; select only those with low or moderate stability. |
|
Multiple PCR product bands due to false priming within and near the intended amplificationregion. |
PCR,Sequencing |
Select only oligos that will not fales prime within and near the PCR product on the target DNA. |
Determine the propensity of false priming using tstability (delta G) calculations; select oligos with no strong priming affinity to any other region on the target sequence. |
|
Background due to false priming and much of the sample is known, including related available sequence files. |
PCR,Sequencing |
Select oligos which will not false prime on known sequence other than the target sequence |
False Priming Check Against Other Sequence Files: Check for false priming sites in all the sequence files selected by the user. |
|
High background due to false priming in repetitive sequence region in the target, e.g., ALU sequences. |
PCR,Sequencing |
Select oligos which will not false prime in repetitive sequence ;-) |
Check for false priming sites in known repetitive sequences downloaded and selected by the user. |
|
Low efficiency priming because of 3-prime dimerizing and hairpin loop formation of the primer itself. |
PCR,Sequencing |
Select oligos with low dimer and hairpin formation potential at their 3-prime ends. |
Check the 3-prime ends of all oligos using stability algorithms, eliminae those with dimer or hairpin potential. |
Table adapted from the Oligo Primer Analysis Software User Manual (v.6), Section 12.3, p. 233
Tm and other Calculations
Oligo Calc is a very nice oligonucleotide property calculator (e.g. Tm, molecular weight, GC%, etc.)


