Effect of bone grinding on the quantity and quality of DNA obtained from aged trabecular bones

The process of grinding bone into fine powder is widely used to improve DNA recovery from skeletal material. However, mechanical and thermal stresses generated during grinding may contribute to DNA degradation. To evaluate the effect of bone grinding on the quality and quantity of DNA obtained from aged skeletal remains, 59 paired trabecular-rich metacarpal epiphyses recovered from the post-Second World War mass grave were processed using two extraction approaches: one employing powdered bone and the other intact bone fragments. DNA quantity and quality were evaluated by qPCR PowerQuant analyses, and autosomal STRs were typed to assess genotyping success. Our results revealed significantly higher DNA yield in bone powder than in bone fragments. The degradation index (Auto/Deg ratio) and allele drop-outs were greater in fragment samples, indicating higher DNA degradation. STR typing confirmed that powdered samples produced more complete profiles compared to fragments. These findings suggest that mechanical grinding, when performed under controlled conditions with liquid nitrogen cooling, does not impair DNA integrity and enhances recovery efficiency for the tested bone type and methods used. Therefore, despite the simplicity of fragment processing, we recommend grinding for optimal DNA recovery and reliable genetic identification from aged bones when trabecular bones are processed.