Intra- and Interskeletal Proteome Variations in Fresh and Buried Bones

Proteomic methods are acquiring greater importance in archaeology and palaeontology due to the longevity of proteins in skeletal remains. There are also developing interests in forensic applications, offering the potential to shed light on post-mortem intervals and age at death estimation. However, our understanding of intra- and interskeletal proteome variations is currently severely limited. Here, we evaluated the proteomes obtained from five distinct subsamples of different skeletal elements from buried pig carcasses to ascertain the extent of variation within and between individuals. We found that reproducibility of data depends on the skeletal element used for sampling and that intrabone differences exceed those observed between the same skeletal element sampled from different individuals. Interestingly, the abundance of several serum proteins appeared to correlate with biological age with relative concentrations of alpha-1 antitrypsin and chromogranin-A increasing and those of fetuin-A decreasing. We also observed a surprising level of divergence in data from different LC-MS/MS runs on aliquots of similar samples analyzed months apart, adding constraints to the comparison of results of such methods across different studies.