Genetic Evidence of African Slavery at the Beginning of the Trans-Atlantic Slave Trade

Abstract

An archaeological excavation in Valle da Gafaria (Lagos, Portugal), revealed two contiguous burial places outside the medieval city walls, dating from the 15th–17th centuries AD: one was interpreted as a Leprosarium cemetery and the second as an urban discard deposit, where signs of violent, unceremonious burials suggested that these remains may belong to slaves captured in Africa by the Portuguese. We obtained random short autosomal sequence reads from seven individuals: two from the latter site and five from the Leprosarium and used these to call SNP identities and estimate ancestral affinities with modern reference data. The Leprosarium site samples were less preserved but gave some probability of both African and European ancestry. The two discard deposit burials each gave African affinity signals, which were further refined toward modern West African or Bantu genotyped samples. These data from distressed burials illustrate an African contribution to a low status stratum of Lagos society at a time when this port became a hub of the European trade in African slaves which formed a precursor to the transatlantic transfer of millions.

Dental Modifications in a Skeletal Sample of Enslaved Africans Found at Lagos (Portugal)

“…These slaves were captured in the inland areas of sub‐Saharan Africa being probably of different ethnicities, bought by the Portuguese in the West African coast (mainly from the current Mauritania to the Gulf of Guinea), shipped in several locations, and brought to the Lagos harbour (Fonseca, ; Caldeira, ). Recently, random short autosomal sequence reads from some Lagos individuals, using them to call SNP identities and estimate ancestral affinities with modern reference data, were obtained (Martiniano et al ., ). African affinity signals were identified and further refined toward modern West African or Bantu genotyped samples, as expected from the aforementioned historical sources.…”

Discarded in the trash: Burials of African enslaved individuals in Valle da Gafaria, Lagos, Portugal (15th–17th centuries)

“…The osteological collection of African‐enslaved individuals of Lagos is composed of 158 individuals: 50 non‐adults, 107 adults (30 males, 58 females, 19 of unknown sex), and one individual whose poor state of preservation prevented the estimation of his/her biological profile. Ancestry estimation was performed based on morphometric (Coelho et al, ; Navega et al, ) and genetic (Martiniano et al, ) analyses. Age at death of non‐adults was achieved on the basis of dental development (i.e., dental calcification and sequence of formation and eruption of teeth) and skeletal development (i.e., long bones' lengths; Wasterlain et al, ).…”

“…Ancestry estimation was performed based on morphometric (Coelho et al, 2017;Navega et al, 2015) and genetic (Martiniano et al, 2014) analyses. Age at death of non-adults was achieved on the basis of dental development (i.e., dental calcification and sequence of formation and eruption of teeth) and skeletal development (i.e., long bones' lengths; Wasterlain et al, 2018).…”

“…Anthropological analyses of the human skeletons revealed a morphology characteristic of African ancestry (Coelho, Navega, Cunha, Ferreira, & Wasterlain, ; Navega et al, ), as well as the presence of intentional tooth modifications in many individuals (Wasterlain, Neves, & Ferreira, ). The genetic study of four skeletons confirmed their African ancestry affinity with Bantu‐speaking groups (Martiniano et al, ). Unfortunately, as thoroughly explained in Wasterlain et al (), it was not possible to infer a more specific origin for these individuals.…”

The early colonial atlantic world: New insights on the African Diaspora from isotopic and ancient DNA analyses of a multiethnic 15th–17th century burial population from the Canary Islands, Spain

“…NGS analysis also provides information about damage patterns and fragment length distribution, which are crucial for authenticating aDNA results. For those reasons, NGS and/or whole–genome analysis are now preferentially used for aDNA analysis, including slavery studies (Martiniano et al, ; Schroeder et al, ). As an example, in a recent publication analyzing enslaved Africans remains excavated on the island of Saint Martin, authors were able to link the remains not only to Africa, but also to subcontinental areas within Africa using NGS (Schroeder et al, ).…”