Human Microevolution and the Atlantic Slave Trade: A Case Study from São Tomé

Populations derived from the Atlantic slaving process provide unique opportunities for studying key evolutionary determinants of current patterns of human cultural and biological variation. Examination of the genetic patterning of the small plantation island of São Tomé (Gulf of Guinea) using a study design that avoids the use of preconceived ethno-linguistic labels to define genetic sampling units reveals that, despite the fact that maximum distance between any two sampled sites is less than 50 km, the island has an unusual level of genetic structure that is mainly caused by the grouping of Angolar Creole-speakers in a separate cluster carrying a distinctive imprint of genetic drift. This pattern may have been shaped by a kin-structured founder effect associated with the flight of a patrilineal clan of rebel slaves who established a remarkably successful maroon community in the vicinity of the plantation complex. The observation that population-discontinuous jumps may occur even under social conditions of massive coercive amalgamation provides an illustration of the way in which human clusters emerge and eventually shape the genetic background of human populations.