Genomic analysis of pre-conquest human remains from the Canary Islands reveal close affinity to modern North Africans

The origins and genetic affinity of the aboriginal inhabitants of the Canary Islands, commonly known as Guanches, is poorly understood. Though radiocarbon dates on archaeological remains such as charcoal, seeds, ash sediments and domestic animal bones suggest that people have inhabited the islands since the 5th century BCE, it remains unclear how many times and by whom, the islands were first settled. Previously published ancient DNA analysis of uniparental genetic markers have shown that the Guanches carried common North African Y-chromosome markers (E-M81, E-M78 and J-M267) and mitochondrial lineages such as U6b, in addition to common Eurasian haplogroups. These results are in agreement with some linguistic, archaeological and anthropological data indicating an origin from a North African Berber-like population. However, to date there are no published Guanche autosomal genomes to help elucidate and directly test this hypothesis. To resolve this, we generated the first genome-wide sequence data and mitochondrial genomes from eleven archaeological Guanche individuals originating from Gran Canaria and Tenerife. Five of the individuals (directly radiocarbon dated to a time transect spanning the 7th - 11th centuries CE) yielded sufficient autosomal genome coverage (0.21x to 3.93x) for population genomic analysis. Our results show that the Guanches were genetically homogeneous over time, suggesting a single source population, and that they display the greatest genetic affinity to extant Northwest Africans, strongly supporting the hypothesis of a Berber-like origin. We also estimate that the Guanches have contributed 16-31% autosomal ancestry to modern Canary Islanders.