Ancestry estimation based on cranial measurements: a custom made approach

The estimation of ancestry is an essential benchmark for positive identification of heavily decomposed bodies that are recovered in a variety of death and crime scenes. This is especially true when reconstructing the biological profile of the deceased as most methods for sex, age and stature estimation are population-specific. Ancestry estimation methods vary from traditional morphological assessment of cranial features and biometric quantification to computer-aided shape analysis and classification with specialised software. The current paper aims to explore population differences between three neighbouring countries (Greece, Cyprus and Turkey) that have been in constant interaction through conflicts and population movements from the ancient past to the present day, through cranial measurements. The sample consists of 160 dry crania of Greek origin, 137 dry crania of Greek-Cypriot of origin Cyprus and 380 CT scans from Turks individuals. Twelve measurements were taken in both dry and virtual skulls. Data were submitted to principal component analysis and discriminant function analysis. Intra- and inter-observer error as well as the measurement error between virtual and physical measurements were quantified using TEM, rTEM and R. Measurement error was very low in all cases. Classification accuracy for cross-validated data ranged from 74.1 to 97.9%. The highest accuracy was obtained for the Turks sample both in males and females. The results are in accordance with genetic data on the three populations. These results create great confidence in the application of the produced functions in forensic cases requiring ancestry estimation in Cyprus, specifically to unidentified individuals from the 1974 conflict. In addition, these standards can be applied in other forensic situations where ethnicity is an issue but the geographic area of origin is limited to the area encompassing Turkey, Cyprus and Greece