Ancestry Estimation in Forensic Anthropology: Geometric Morphometric versus Standard and Nonstandard Interlandmark Distances

Abstract

Standard cranial measurements are commonly used for ancestry estimation; however, 3D digitizers have made cranial landmark data collection and geometric morphometric (GM) analyses more popular within forensic anthropology. Yet there has been little focus on which data type works best. The goal of the present research is to test the discrimination ability of standard and nonstandard craniometric measurements and data derived from GM analysis. A total of 31 cranial landmarks were used to generate 465 interlandmark distances, including a subset of 20 commonly used measurements, and to generate principal component scores from procrustes coordinates. All were subjected to discriminant function analysis to ascertain which type of data performed best for ancestry estimation of American Black and White and Hispanic males and females. The nonstandard interlandmark distances generated the highest classification rates for females (90.5%) and males (88.2%). Using nonstandard interlandmark distances over more commonly used measurements leads to better ancestry estimates for our current population structure.

Metric variation of the tibia in the Mediterranean: Implications in forensic identification

“…An obvious disadvantage of these methods is the lack of a reference sample for every population which would inevitably result in erroneous classifications of target individuals not represented in the databases. This is supported by several validation studies [13][14][15].…”

The geometrical precision of virtual bone models derived from clinical computed tomography data for forensic anthropology

“…The use of non-standard methodological approaches enables us to explore the range and pattern of human variation from a different angle and ultimately may lead to the development of innovative osteometric techniques. The benefit of this approach is illustrated by recent work which showed that integrating non-standard measurements provides more information for complex population structures where there is a high rate of immigration, migration and relaxed border controls [43]. Additionally, virtual models derived from clinical CT data enable us to develop new forensic anthropological techniques that are not based on biased skeletal databases.…”

The Biological Profile of Unidentified Human Remains in a Forensic Context

“…Another study used GM to assist in distinguishing between Hispanics and American blacks and whites, an ancestry estimation that has previously been difficult to perform accurately with traditional craniometrics (38). Geometric morphometric analysis has not yet been shown to be more accurate than traditional linear measurement methods, but these types of methods are still being refined (59,60).…”

“…The three-dimensional nature of GM data in its original state allows for the study of shape without size influences, which can incorporate sophisticated statistics into the formation of biological profiles. While GM can be used to test a variety of hypotheses (46,47), several methods have been developed in recent years to estimate sex and ancestry from cranial, dental, and postcranial information with varying degrees of success (38,(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59). The most holistic of these methods is 3D-ID, a computer program that acts in much the same way as Fordisc to produce sex and ancestry estimates of an unknown cranium (54).…”