Targeting Optimal Bone Regions: Correlations Between Bone Density and DNA Quality in Small Skeletal Elements.

Abstract

Background: Identifying the optimal bone regions for DNA analysis is critical, as DNA preservation and quality vary significantly across bone types and structures and is defined as intra-bone variability. This study aimed to evaluate the correlation between computed tomography (CT)-measured bone density and DNA preservation in small skeletal elements to identify optimal regions for DNA analysis. Methods: 137 bones from six skeletal elements excavated from a single burial site were analysed using Dual-Source CT (DSCT) to map compact and cancellous regions. DNA was extracted using a demineralisation method and quantified via real-time PCR to assess DNA quantity and degradation. Results: Among 461 bone regions analysed (137 bones; patellae, calcaneus, talus, the navicular bones, the cuboid bone, and the medial cuneiform bone), a significant difference in DNA quantity was observed only in the calcaneus, where the sulcus contained more DNA than the body. No significant differences in the degradation index were detected among bone segments or skeletal elements. Correlations between CT-measured bone density and DNA quantity or degradation index were region-specific. Higher bone density correlated positively with DNA quantity in compact regions of the calcaneus and talus. Regarding degradation, a positive correlation (higher bone density → higher degradation) was observed in the patella's anterior surface, while a negative correlation (higher bone density → lower degradation) was found in the talus's sulcus, the opposite side of the talar sulcus, the posterior calcaneal articular facet, and the cuboid's tuberosity. No significant correlations were found in other bone segments. Conclusions: Our study identified small skeletal elements, particularly the patella and the navicular bone, as promising sources for DNA analysis. While bone density correlated with DNA preservation in some cases, the relationship was inconsistent. Our findings support the use of small bones in forensic and archaeological research and warrant further investigation.