Journal
INTERNATIONAL JOURNAL OF LEGAL MEDICINE
Volume 135, Issue 1, Pages 63-72Publisher
SPRINGER
DOI: 10.1007/s00414-020-02363-4
Keywords
PCR inhibition; Metal ions; DNA polymerase; EGTA
Categories
Funding
- Leverhulme Trust [RC-1015-01]
Ask authors/readers for more resources
Metal ions can inhibit PCR in forensic DNA analysis, especially in samples from crime scenes. Zinc, tin, iron(II), and copper show strong inhibitory effects on DNA amplification, while KOD polymerase exhibits the highest resistance to metal inhibition. Ethylene glycol-bis(2-aminoethylether)-N,N,N ',N '-tetraacetic acid (EGTA) can effectively reverse calcium-induced PCR inhibition.
Inhibition of PCR by metal ions can pose a serious challenge in the process of forensic DNA analysis. Samples contaminated with various types of metal ions encountered at crime scenes include swabs from metal surfaces such as bullets, cartridge casings, weapons (including guns and knives), metal wires and surfaces as well as bone samples which contain calcium. The mechanism behind the impact of metal ions on DNA recovery, extraction and subsequent amplification is not fully understood. In this study, we assessed the inhibitory effects of commonly encountered metals on DNA amplification. Of the nine tested metals, zinc, tin, iron(II) and copper were shown to have the strongest inhibitory properties having IC50 values significantly below 1 mM. In the second part of the study, three commercially available DNA polymerases were tested for their susceptibility to metal inhibition. We found that KOD polymerase was the most resistant to metal inhibition when compared with Q5 and Taq polymerase. We also demonstrate how the calcium chelator ethylene glycol-bis(2-aminoethylether)-N,N,N ',N '-tetraacetic acid (EGTA) can be used as an easy and non-destructive method of reversing calcium-induced inhibition of PCR reactions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available