Examination of DNA yield rates for different skeletal elements at increasing post mortem intervals

Area of Science:

• Forensic Anthropology
• Molecular Biology
• Human Identification

Background:

• DNA Short Tandem Repeat (STR) testing is crucial for identifying human remains.
• Successful DNA profiling depends on isolating sufficient DNA from skeletal samples.
• Skeletal element selection significantly impacts DNA yield and profile quality.

Purpose of the Study:

• To compare DNA yields and STR profile success rates from various skeletal elements.
• To evaluate the influence of post-mortem interval (PMI) on DNA recovery from different bone types.
• To reassess current recommendations for skeletal sample selection in forensic DNA analysis.

Main Methods:

• DNA extraction from 55 bone samples across diverse skeletal elements from 3 recently skeletonized individuals.
• Analysis of DNA yields and 16-locus STR profiles.
• Testing of 10 skeletal elements from 12 additional skeletons with varying PMIs (3-21 years).

Main Results:

• Small, cancellous bones yielded significantly higher DNA quantities per unit mass compared to dense cortical bones.
• Complete 16-locus STR profiles were achieved from 36 element types across all individuals.
• Cancellous bones consistently provided more DNA and STR loci than cortical bones, even with extended PMIs.

Conclusions:

• The study challenges the conventional recommendation of using long cortical bones for DNA testing.
• Cancellous bone elements are superior for DNA extraction in forensic identification cases.
• Optimized skeletal element selection can enhance the success rate of DNA profiling from human remains.