Assessing the Accuracy, Validity, and Application of a New Method for Sex Estimation Using Isotopic Ratios of FE, CU, and ZN in Human Bone

This dissertation evaluates the accuracy, validity, and application of a novel sex determination method based on isotopic variations in copper (Cu) and iron (Fe) within human bone, initially developed by Jaouen et al. (2012). The primary aim of this research was to test the reproducibility of the method, expand the sample to include a broader age range and ethnically diverse groups, and assess its applicability in forensic contexts using contemporary skeletal samples. Bone samples were collected from 60 individuals across two curated skeletal collections: the George S. Huntington Skeletal Collection and the Texas State Forensic Anthropology Donated Skeletal Collection. The elemental concentrations and isotopic ratios of Cu and Fe were analyzed using Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). Key findings reveal that the method does not produce statistically significant results for sex determination across the diverse sample set. No significant differences in isotopic concentrations or ratios were attributable to sex or ancestry. However, statistically significant differences in iron isotope ratios were observed between age groups, particularly between mature adult and older adult females, suggesting that age-related metabolic processes may affect elemental inventories and isotopic signatures left in bone. Despite these findings, the accuracy of this method was not comparable to other morphometric and molecular sex estimation techniques. These results indicate that further research is necessary to assess the efficacy of this method, particularly in relation to age-related changes in human biogeochemistry. This study underscores the need for additional testing using broader demographic samples to improve the applicability of isotopic analysis as a method of sex estimation to the discipline of biological anthropology.