The petrous advantage in perinatal and early childhood remains: A paired study of forensic DNA recovery.

Human identification from skeletal remains is challenging in forensic genetics, particularly when DNA is highly degraded. The skeletal element selected for analysis strongly influences DNA recovery and STR profiling success. This study compared the petrous part of the temporal bone with paired conventional skeletal elements for forensic DNA analysis in degraded perinatal and early childhood remains. The study included 54 individuals aged 0-7 years recovered from two twentieth-century historical mass grave sites in Poland. For each individual, DNA was extracted from the petrous part of the temporal bone and from a paired reference skeletal element. DNA quantity and degradation were assessed using the Quantifiler™ Trio DNA Quantification Kit, and autosomal STR and Y-STR profiling were performed using the GlobalFiler™ and Yfiler™ Plus PCR Amplification Kits. Paired comparisons evaluated DNA preservation, STR profile completeness, signal intensity, dropout, and practical profile utility. Petrous bone markedly outperformed paired reference material. Mean autosomal STR profile completeness was 0.900 for petrous bone and 0.224 for reference material, while the mean number of detected autosomal loci was 18.9 and 4.7, respectively. Full autosomal STR profiles were obtained from 34/54 petrous samples (63.0%) but from only 1/54 reference samples (1.9%). Petrous samples also showed lower dropout and higher RFU signal intensity. Using a strict salvage criterion, petrous sampling rescued 40/54 cases (74.1%) in which paired reference material yielded low-informative profiles. These findings demonstrate that petrous bone substantially improves STR profiling success in degraded perinatal and early childhood skeletal remains and should be preferentially considered when conventional skeletal elements are likely to provide limited genetic information.