Reconstructing life history and ancestry from poorly preserved skeletal remains: A bioanthropological study of a Copper Age infant from Faenza (RA, Italy)

The poor preservation of archaeological skeletal remains, particularly those of infants, can result in partial representations of populations and significantly limit our understanding of the development and life of their infant segment. This study investigates the potential of combining dental histology, high spatial resolution biogeochemistry, radiocarbon dating, palaeoproteomic and ancient DNA (aDNA) analyses alongside traditional osteological methods to reconstruct the biological profile and life history of the heavily degraded skeletal remains of an infant from Faenza, Italy.

Severe skeletal degradation left only dental crowns and small osseous fragments, restricting traditional osteological analysis to an estimation of the age at death. Histological analysis of two dental specimens, a deciduous upper right first molar and a permanent lower right first molar, provided detailed insights into the infant's development, ultimately refining the age at death at approximately 17 months. Biogeochemical analysis using Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS) revealed pronounced diagenetic alterations masking the original biogenic signal. Proteomic analysis of enamel peptides and genomic analysis of the osseous fragments identified the infant's sex as male. Genomic analysis, facilitated by a sufficient quantity of endogenous aDNA, enabled the reconstruction of the mitochondrial genome, providing valuable insights into the matrilineal ancestry of the individual and identifying an uncommon mtDNA haplogroup for the Eneolithic period in the Italian peninsula.

Despite the limited preservation of the skeletal elements, the combined application of advanced bioanthropological techniques demonstrated the substantial informative potential inherent in even a few preserved anatomical elements. This study underscores the critical value of multidisciplinary approaches in overcoming the challenges posed by highly degraded remains, revealing insights that would otherwise remain inaccessible.