Forensic DNA typing from teeth using demineralized root tips.

Area of Science:

• Forensic Science
• Human Genetics
• Molecular Biology

Background:

• Teeth are crucial for forensic genetic identification due to their durability.
• Current tooth processing methods for DNA extraction are largely unchanged and often involve destructive techniques like powdering.
• There is a need for simpler, less equipment-intensive methods for postmortem dental DNA analysis.

Purpose of the Study:

• To present demineralized tooth root tips as a viable source for nuclear DNA extraction.
• To develop a low-tech, non-destructive method for processing teeth in forensic casework.
• To evaluate the efficiency of DNA recovery and profile generation from demineralized root tips.

Main Methods:

• Whole teeth from unidentified human bodies were demineralized using EDTA solution.
• The final millimeters of the root tip were excised after demineralization.
• DNA was extracted using a conventional organic protocol, followed by quantification and STR amplification.
• Short tandem repeat (STR) analysis was performed using commercial kits and capillary electrophoresis.

Main Results:

• Full genetic profiles were obtained from the first root tip extraction in 60% of cases.
• Complete genetic profiles were achieved for 85% of the individuals studied.
• A high rate of positive identification (80%) was achieved using this method.

Conclusions:

• Demineralized tooth root tips are effective sources of nuclear DNA for forensic identification.
• This alternative method is low-tech, requires no expensive equipment, and avoids sample powdering.
• The approach provides sufficient DNA quantity and quality for forensic casework, even after demineralization.