Introduction
DNA recovery from skeletal remains is crucial in forensic and archaeological contexts, but it depends on the bone structure, density, and burial conditions. While the petrous bone yields the most DNA, its destructive sampling limits applicability. This study assessed the potential of six small skeletal elements as alternative sources for DNA for molecular genetic identification.
Materials and Methods
We analysed 137 bones (patella, calcaneus, talus, navicular, cuboid, medial cuneiform) from a post-WWII mass grave. Dual-source CT was used with a specially adapted and study-specific protocol to map compact and cancellous bone and determine ROI for measuring bone density in HU. Subsequently, 25 archaeological patellae were selected for comparison. After cleaning and CT-guided sectioning, the bone powder was processed using full demineralisation protocols. DNA was purified and quantified by quantitative PCR (qPCR). Eighteen samples underwent autosomal STR typing. Due to the non-normal distribution of the data, statistically significant differences were analysed with 95% confidence intervals and correlations using Spearman’s correlation test.
Results
DSCT revealed unique bone microarchitectures, enabling precise selection of sampling sites. Significant intra-bone variation in DNA yield occurred only in the calcaneus (sulcus > body). Patellae and navicular bones consistently yielded the highest DNA preservation, while talus and calcaneus showed greater degradation. Bone density correlated inconsistently with DNA yield across elements. STR typing was successful in all tested samples, with complete profiles confirming authenticity. Patellae exhibited context-dependent variation: post-WWII specimens produced higher yields and fuller profiles compared with more degraded archaeological samples, reflecting time-since-burial effects.
Conclusions
Small skeletal elements, particularly patellae and navicular bones, provide reliable alternatives to petrous sampling for forensic and archaeological DNA investigations. DSCT imaging proved effective for identifying optimal sampling regions, reducing destructive practices, and ensuring consistent intra-bone comparisons. The study confirms the usefulness of the patella as a high-quality and morphologically distinctive skeletal element for forensic and archaeological DNA analysis. Our results demonstrate that burial and environmental conditions, as well as bone density, significantly influence DNA preservation and yield, with time being the most decisive factor.
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