preCR

PreCR, or PreCR DNA Repair Mix, is a proprietary enzymatic formulation developed by New England Biolabs for repairing damaged DNA prior to amplification or sequencing. It is designed to restore the ability of degraded or chemically damaged DNA to serve as a template in PCR and library preparation, thereby increasing yield and success rates for challenging samples.

The mix combines multiple DNA repair activities that target a broad range of lesions. Through coordinated action of damaged-base excision, strand-break repair, gap-filling, and nick sealing, it can convert damaged templates into more intact double-stranded DNA. The exact enzymatic composition is proprietary, but the product is intended for use on damaged DNA from sources such as aged specimens, forensic samples, or formalin-fixed tissues.

Applications include improving amplification of degraded DNA, enabling sequencing library construction, and salvaging DNA for cloning. It is commonly used in ancient DNA studies, forensic analyses, and clinical sample workflows where DNA integrity is compromised.

Limitations: repair is not guaranteed for all damage types; some damaged bases may be repaired into incorrect sequences, introducing bias. Fragmented DNA may remain short, and extremely damaged samples may not become fully amplifiable. Users should optimize reaction conditions and include appropriate controls.

See also: DNA repair, ancient DNA, next-generation sequencing, FFPE.