Optimization of Method for Human Sex Determination Using Peptidome Analysis of Teeth Enamel from Teeth of Different Biological Generation, Archeological Age, and Degrees of Taphonomic Preservation.

Determination of biological sex to human remains is a fundamental requirement in anthropological, archeological, and forensic anthropological studies. Sex determination based on morphological criteria is significantly limited in the cases of juvenile remains and adult skeletons in a poor state of preservation. Regular attempts have been made to use alternative techniques to resolve this issue, including analysis of tooth enamel peptides by liquid chromatography/mass spectrometry. Optimization of this method involving acid etching of tooth enamel for 10 min followed by desalting of the products of etching on SDB-RPS StageTips microcolumns and analysis of desalted sample (1/3) by liquid chromatography/mass spectrometry allowed reliable sex determination to fossil remains within a wide range of archeological and biological ages without destructing analyzed teeth. Increasing the duration of enamel etching ensured a 2 to 3-fold increase in the total number of identified peptides and, more importantly, in the number of identified fragments of amelogenin Y isoform specific for male teeth, which facilitated reliable sex determination of fossil remains. The suggested technique was tested with 8 permanent and 15 deciduous teeth of different archaeological age and different degree of preservation. Two amelogenin Y-specific peptide sequences were identified. One of these peptides [SM(+15.99)IRPPYS)] was found in all male-derived samples without exception; the other peptide [IRPPYSS(+79.97)], which contained phosphorylated Ser66 residue, was found only in the enamel from deciduous teeth, which suggests that phosphorylation of Ser66 plays a role in the enamel formation in deciduous teeth.