It has become a widespread practice to convert δ(18)O(p) values measured in human and animal dental enamel to a corresponding value of δ(18)O(w) and compare these data with mapped δ(18)O(w) groundwater or meteoric water values to locate the region where the owner of the tooth lived during the formation of the enamel. Because this is a regression procedure, the errors associated with the predicted δ(18)O(w) values will depend critically on the correlation between the comparative data used to perform the regression. By comparing four widely used regression equations we demonstrate that the smallest 95% error is likely to be greater than ±1% in δ(18)O(w) , and could be as large as ±3.5%. These values are significantly higher than those quoted in some of the recent literature, and measurements with errors at the higher end of this range would render many of the published geographical attributions statistically unsupportable. We suggest that the simplest solution to this situation is to make geographical attributions based on the direct comparison of measured values of δ(18)O(p) rather than on predicted values of δ(18)O(w).
The Basques have a well-documented history of migration and settlement in the Americas, and they often retain cultural identity across generations. Numerous genetic studies have been carried out on European Basques; thus, immigrant Basques are an ideal population for investigating the genetic consequences of a recent human migration event. We have sampled 53 unrelated individuals with Basque ancestry in Boise, Idaho and determined the mitochondrial DNA (mtDNA) sequence variation of the first and second hypervariable regions. Thirty-six mtDNA haplotypes were detected in our sample. We found evidence of genetic changes consistent with founder effects, which is compatible with the known history of migration. Compared with the European Basque population, the immigrant Basques are significantly different in terms of haplogroup frequency distribution and diversity. They have a lower measure of weighted intralineage mean pairwise diversity (WIMP) and greater genetic distance from other European populations. These data indicate that this immigrant Basque population has experienced a reduction in genetic diversity compared with the putative source population. However, this loss of diversity is not detectable using indices of demographic history such as Tajima's D and Fu's F. This study represents the first description of mtDNA diversity in an immigrant Basque population, and our findings indicate that founder effects accompanying this relatively recent migration event have shaped the genetic diversity of this population.
This study analyzed skeletal health disparities among African American and Euro-American males of low socioeconomic status born between 1825 and 1877. A total of 651 skeletons from the Cobb, Hamann-Todd, and Terry anatomical collections were macroscopically examined for skeletal pathologies related to dietary deficiencies and disease. Individuals were separated into age, ancestry, birth (Antebellum, Civil War, Pre-Reconstruction, and Reconstruction), combined ancestry/birth, enslaved versus liberated, and collection cohorts. These groups were statistically evaluated using ANOVA and χ(2) analyses to determine if age, ethnic, and temporal differences existed. Results indicated that African Americans, especially those born during Reconstruction, had significantly higher frequencies of tuberculosis (P = 0.004) and treponematosis (P = 0.006) than Euro-Americans. Historical sources are important in contextualizing why these different ethnic and temporal patterns were present, pointing to environmental conditions related to enslavement, postliberation migration to the industrialized North, crowded urban living conditions, and poor sanitation.