All glossary terms

PCR artifacts

Over-Amplification

Over-amplification is what happens when a PCR run is cycled too long, depleting reagents and generating artifacts exponentially.

What is over-amplification in PCR?

The damage is not reversible downstream: chimeras, jackpotting, and recombination all trace back to cycling past the point where the reaction should have stopped.

Size Bias

Size bias is the tendency of PCR to preferentially amplify shorter fragments, distorting the original fragment size distribution.

Recombination

Recombination is the unintended shuffling of genetic material between fragments, often driven by over-amplification.

Primer Dimers

Primer dimers are artifacts formed when two primer molecules hybridize to each other instead of to the target DNA template.

Jackpotting

Jackpotting is the runaway over-amplification of a few random fragments, which skews their representation in the sequencing data.

Chimeras

Chimeras are artifacts formed when fragments from different DNA molecules fuse into a single artificial hybrid sequence.

Adapter Dimers

Adapter dimers are artifacts formed when two sequencing adapters ligate to each other instead of to a DNA insert.