A Peptidomics Method for Assessing Sex from Modern and Ancient Bovine Tooth Enamel.

Abstract

Identification of the sex of fossil and archaeological animal remains offers many insights into their demography, mortality profile and domestication pathways. However, sex determination of fossils is often impossible due to the absence of sex-specific diagnostic features on the remains or ambivalence in extrapolating dimorphism from body size and limited organic material preservation for analysis using aDNA. To counter this, we have developed an innovative protocol employing peptidomic techniques of tooth enamel in bovines. We discovered male-specific amino acid variations in AmelY (Asp44, Leu46, Tyr48 and Val58) unique to modern cattle and then successfully applied this same method to sex bovine tooth enamel from Neolithic sites in the Southern Levant (ca. 9,000 BP). We also compared diagenesis of AmelX using peptide length and site-specific post-translational modifications. Additionally, site-specific post-translational modifications (PTMs) of AmelX were identified and can be used to validate the antiquity of ancient enamel. Since teeth are usually better preserved than bones in the fossil and archaeological record, this innovative protocol has the potential to enable sex-determination is ancient bovine remains that currently cannot be sexed.