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.