ROOTS · Ancient DNA and the Atlantic Slave Trade: A Search for Origins

Ancient DNA and the Atlantic Slave Trade: A Search for Origins

The original stated aim of the ROOTS project was to exploit ancient DNA techniques to gain a better understanding of the origins of enslaved Africans who were brought to the Americas with the Atlantic slave trade. Between the sixteenth and nineteenth centuries between 12-15 million Africans were forcibly moved from Africa to the Americas as a result of the transatlantic slave trade. Shipping records offer important insights into the volume and structure of the slave trade, as well as the slaves' origins in Africa. However, since the records usually refer to the place, where slaves were purchased, rather than where they actually originated, it has been very difficult to be precise on ethnic origins. The principal aim of the ROOTS project was to investigate the potential of using ancient DNA data to shed light on the biogeographical origins of enslaved Africans, who were brought to the Caribbean with the slave trade and to identify their source populations in West Africa. More specifically, the project aimed at: i) investigating the feasibility of retrieving aDNA from skeletal material from archaeological contexts that are usually considered to be suboptimal for DNA preservation, i.e. the Caribbean; ii) developing analytical and laboratory techniques (PCR-based approaches, target enrichment and capture techniques, next-generation sequencing) to study aDNA from these contexts; iii) analysing the data both in terms of aDNA damage patterns and ancestry related information that might yield clues to the origins of the individuals under study. The outcomes of this research have been extremely valuable, demonstrating (a) that it is possible to retrieve endogenous DNA from archaeological skeletal material from contexts other than those usually associated with aDNA research, such as permafrost. Although the material is comparatively young, the retrieval of authentic aDNA sequences from skeletal material from archaeological contexts in the Caribbean forms a significant step forward in aDNA research as it opens up a whole new area for future research. Further, the research has shown that (b) when coupled with next-generation sequencing, targeted sequence capture can be an extremely powerful method to isolate, amplify and analyse specific sequences of DNA. Thus, the research has shown that it is possible to retrieve complete mitochondrial genomes using multiplexed targeted sequence capture and high-throughput sequencing. This, the retrieval of full mitochondrial genomes, has allowed us to (c) significantly increase the phylogenetic resolution of the molecular analyses when compared to earlier studies that were based exclusively on the first hypervariable segment of the mitochondrial genome (Salas et al. 2004, 2005). However, despite the significant increase in phylogenetic resolution, the research has shown that (d) it is still not possible to trace the maternal ancestry of individuals beyond broad geographic regions in Africa. Considerable caution is therefore warranted when dealing with claims in the popular media and those made by genetic ancestry-testing companies about their ability to trace the ancestry of certain American (or, for that matter, European) lineages to a particular locale or population within modern-day Africa. The results of the research are currently being prepared for publication.

Data: CORDIS, © European Union