The OligoAnalyzer™ Tool is a free, web-based software developed by Integrated DNA Technologies (IDT) that allows researchers to evaluate oligonucleotide properties before ordering them for PCR, qPCR, sequencing, or cloning. It serves as a digital troubleshooting workbench to ensure primers bind to their target DNA rather than destroying reaction efficiency by binding to themselves. Core Functions & Key Benchmarks
The tool analyzes three primary problematic secondary structures using thermodynamic values like Gibbs free energy ( ) and melting temperature ( Tmcap T sub m
Hairpin Analysis: Evaluates whether a single primer will fold back and base-pair with itself. Safe Benchmark: The Tmcap T sub m
of the predicted hairpin must be lower than your PCR annealing temperature. If the hairpin Tmcap T sub m
is higher, it will freeze into a loop and fail to hybridize to your template.
Self-Dimer Analysis: Tests if a primer molecule will hybridize with another identical primer molecule. Safe Benchmark: The calculated value should be greater than (i.e., closer to zero, like ). A highly negative value (
) means the dimer is highly stable and will consume your master mix.
Hetero-Dimer Analysis: Tests if your forward primer will cross-hybridize with your reverse primer, creating classic primer-dimer artifacts. Safe Benchmark: Same as self-dimers; look for a greater than
to ensure the forward and reverse primers do not stick together. How to Use the Tool
You can easily input parameters to match your specific bench conditions:
Paste the Sequence: Enter your oligonucleotide sequence into the analysis window. The tool accepts DNA, RNA, mixed bases, and custom modifications.
Adjust Reaction Parameters: Input your specific chemical concentrations—including monovalent ions ( Na+cap N a raised to the positive power ), divalent ions ( Mg2+cap M g raised to the 2 plus power dNTPsd cap N cap T cap P s
—as these variables drastically change how oligonucleotides fold and bind. You can also use preset parameters for qPCR.
Run the Diagnostics: Click the respective buttons on the right side of the screen (Hairpin, Self-Dimer, or Hetero-Dimer) to map out the physical structures and read the thermodynamic values.
If the software flags a structure exceeding these parameters, you should adjust your primer boundaries by shifting them a few base pairs upstream or downstream on your template. If you are currently designing a specific set of primers, How To Check For Primer-Dimers & Hairpins In Your Oligos
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