Geographic Origin Estimation of Latin American Individuals Using Craniometric Data
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Since 2011, regions in South Texas have experienced a significant increase in migrant deaths and increased apprehensions of non-Mexicans (Isacson & Meyer, 2013). As migrants from countries other than Mexico cross the Texas-Mexico border, it becomes increasingly difficult to determine country of origin as well as identify and repatriate these individuals. The purpose of the present research is to examine craniometric variation among Central American populations to ultimately improve geographic origin estimation for migrants that die crossing the Texas-Mexico border by looking at variation between Mexico and Guatemala, between the regions of Mexico, and how unknown migrant individuals are classifying. In addition, this study will aid in our understanding of the biological variation of Mexican and Guatemalan populations which may facilitate and potentially expedite the identification and repatriation of unidentified migrants. The study sample consists of different geographic population groups including positively identified Guatemalan and Mexican individuals (North/West, Southeast, and Central regions), as well as unidentified and identified OpID remains. Howells, (1973) inter-landmark distances were collected from each cranium using a Microscribe digitizer and the program ThreeSkull (Ousley, 2004). A discriminant function analysis, stepwise function, and canonical variates analysis were performed to look at the variation and classify the individuals. 75.25% of the time Guatemalans can be correctly classified when compared to Mexicans. The cross-validation rate suggests that when the three Mexican regions are compared (Central, Southeast, and North/West) they can be differentiated 77.8% of the time. The Mahalanobis Distance matrix indicates the Southeast group is statistically different from the Central and Northwest groups (p=<0.001). When looking strictly at identified OpID individuals, 68% classified as Guatemalan and 32% as Mexican.
Geographic patterns of morphology are beginning to be observed within Mexico and between Mexico and Guatemala. If Guatemala is used as a proxy for Central America, further exploration with other countries is needed. Considering these patterns, this research indicates geographic origin estimation can be used in lieu of broad ancestry estimation in forensic casework and reference samples need to be reassessed to narrow down the missing persons list and help facilitate identifications of unidentified remains.