A Comparison of Proteomic, Genomic, and Osteological Methods of Archaeological Sex Estimation

Proteomic sex estimation of human remains via liquid chromatography tandem mass spectrometry (LC- MS/MS) of sexually dimorphic amelogenin peptides in tooth enamel. The human remains analyzed in this study were recovered from two archaeological sites, Síi Túupentak (CA-ALA-565; ca. 200-600 cal BP) and Rummey Ta Kuččuwiš Tiprectak (CA-ALA-704/H; ca. 180-2240 cal. BP), Late Holocene ancestral Ohlone villages in Central California. The X and Y chromosomes code for distinctive isoforms of amelogenin proteins, AMELX_HUMAN and AMELY_HUMAN. Fragments of these proteins can be detected using shotgun liquid chromatography mass spectrometry and assigned to the AMELX or AMELY isoform. We use nano-liquid chromatography coupled with orbitrap tandem mass spectrometry (LC-orbitrap-MS/MS). Signals of all peptides that can be unambiguously attributed to either AMELY or AMELX isoforms are summed and normalized for sample weight. Confident detection of AMELY specific peptides provides an unambiguous indicator of a male sex chromosome.