Influence of soil storage and exposure period on DNA recovery from teeth.

A study was performed to determine the influence of garden soil on the deoxyribonucleic acid (DNA) recovery from teeth depending on the duration of storage. In the first series 24 teeth supplied by dentists were exposed to garden soil storage for a maximum of 18 weeks. Selected samples were excavated for DNA extraction at time intervals of 6, 12 and 18 weeks. For the second series 20 teeth were stored for one year in garden soil. Following phenol/chloroform extraction with decalcification (first series) and without decalcification prior to extraction (second series) DNA was quantified, amplified using the polymerase chain reaction (PCR) for the tandem repeat loci D1S80, tyrosine hydroxylase, intron 1 (TH01) and Von Willebrand factor, intron A (VWA) (first series), human alpha fibrinogen (FGA) (second series) and sequenced in the hypervariable regions 1 and 2 (HV1, HV2) of the mitochondrial DNA (second series). The DNA concentration of the extracts after the first 6 weeks in soil was reduced by more than 90%. Amplification and direct sequencing of HV1 and HV2 of the mitochondrial genome was the most successful DNA technique.