Biological Anthropological Aspects of the African Diaspora; Geographic Origins, Secular Trends, and Plastic Versus Genetic Influences Utilizing Craniometric Data

The African Diaspora refers to the forced emigration of Africans to European and British colonies for the purpose of providing slave labor. Enslaved Africans that arrived in the New World were subjected to a new environment and plantation labor. When dramatic shifts in living standards or exposure to a new environment occur, physical changes may take place within the given population. These types of changes over the short-term are known as secular changes and are thought to be the result of an improvement or decline in environmental conditions, particularly nutrition (Cameron et al., 1990).

Significant craniofacial secular changes have been documented in American Whites and Blacks over the past 150 years (Jantz, 2001; Jantz and Meadows Jantz, 2000, Wescott and Jantz, 2005). Angle (1976) also noted changes in colonial to more recent American Blacks and Whites. However, Angel's sample sizes for the time periods he studied were small and he did not test for correlations with time. To date, no studies have exclusively focused on the craniofacial morphological changes taking place since the arrival of Africans to the Americas, some 350 years ago with appropriate samples, and whether these changes result from selection, environment, plasticity, or gene flow (admixture).

The hypothesis of the present research is that significant craniofacial secular change has taken place in the American Black population since the American colonies entered the slave trade. The objectives are to use new craniometric data to trace the geographical origins of enslaved Africans and early American Blacks; to use larger samples with more time-depth and smaller birth year cohorts than previously used to assess the significance of the proposed craniofacial secular changes; and to compare new craniometric and previously published genetic data to evaluate whether or not the observed craniofacial secular changes are a result of environmental plasticity or genetic control. This research suggests that significant craniofacial secular changes have taken place from 1700 to 1975 and that a genetic association with craniofacial morphology is apparent.