Evaluation of carrier RNA and low volume demineralization for recovery of nuclear DNA from human teeth.

PURPOSE

Teeth and bones are frequently used in the genetic analysis of degraded and ancient human and animal remains. Standard extraction methods, including most commercially available systems, may not yield sufficient DNA to enable successful genetic analysis. Addition of a carrier molecule and demineralization (via EDTA) can increase yields from samples containing limited amounts of DNA. However the benefits of carrier molecules have not been demonstrated for bones and teeth and demineralization introduces large reagent volumes that are difficult to integrate into commercial DNA extraction systems.

METHODS

We compared nuclear DNA yields recovered from small samples of partially decomposed human teeth using a commercial silica-based DNA extraction system with and without the addition of carrier RNA and/or a low-volume demineralization step.

RESULTS

DNA yield was significantly improved with demineralization, but there was no significant effect of carrier RNA. The DNA content of a sample did not influence the significance of the effect of demineralization.

CONCLUSION

Using a simple low-volume (1 mL) demineralization step, prior to DNA extraction with the QIAmp DNA Investigator kit (Qiagen), as little as 50 mg of tooth powder can yield more than 500 ng of nuclear DNA.