Evolutionary Genomics of the Trans-Atlantic Slave Trade

Abstract

The Trans-Atlantic Slave Trade is a remarkable large-scale migration in the human history. On several occasions between the 16th and 19th century, millions of African men, women, and children were purchased from African traders and some abducted for slavery by the Europeans, for forced labour in the European colonies established in the American continent. The barbarous nature of the slavery left significant genetic modifications in the ancestry of modern-day descendants of former slaves (African Americans in United States and in Barbados). This research uses differently inherited high coverage Whole Genome Sequences (WGS) from autosomal, X, Y, and low coverage mitochondrial chromosomes collectively to present a detailed genetic point of view of the African Americans, their genetic relations to Africans and their interactions with America’s other residents: Europeans and Native Americans. The results show that African slaves were abducted from West Africa (dominantly from Nigerian populations). Gene flow patterns were observed among former African slaves, their European slave masters, and Native American populations, resulting in genetic diversity among modern-day African Americans that is greater than any other population currently inhabiting the Americas and even higher than their source populations in Africa. The gene flow pattern was unidirectional from Europeans to African Americans and Native Americans, but bidirectional between the African Americans and Native Americans.