DNA Fragmentation
Definition
Physical breakage of the DNA backbone into short pieces. In degraded samples the average fragment length may be 50-200 bp, making long PCR amplicons impossible to form.
- Definition
- Physical breakage of the DNA backbone into short pieces
- Typical degraded fragment length
- 50 to 200 bp
- Consequence
- Long PCR amplicons cannot form
- Common cause
- Sample degradation or processing
Common questions
How do labs still obtain a usable profile from heavily fragmented DNA?+
They switch to assays designed around short amplicons, such as mini-STR kits, which target loci with shorter flanking sequences so amplification can succeed even when the template DNA is broken into small pieces.
Why does fragmentation matter more for processed wildlife products than for typical crime-scene samples?+
Heat, chemical processing, and time degrade DNA further in products like leather, ivory carvings, or traditional medicine ingredients, so standard-length STR kits validated for fresher casework samples often fail outright on these matrices.
Related terms
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- Library Preparation (aDNA)
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- Metagenomics
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- PCR Inhibitor
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- Short-Amplicon Strategy
- A PCR design that targets the shortest possible fragment length: often 80-150 bp: within a diagnostic locus such as COI. Shorter targets...