The aboriginal inhabitants of the Canary Islands, commonly known as Guanches, were genetically most similar to modern North African Berbers, according to an ancient-DNA sequencing study published this week in the journal Current Biology.
Guanches. Image credit: Gran Enciclopedia Virtual de las Islas Canarias.
When and how the Guanches arrived to the Canary Islands have remained poorly understood, not least since they lacked boats and the knowledge of how to navigate the surrounding seas.
In fact, when Europeans colonized the islands in the 15th century CE they discovered a culture that much resembled Neolithic cultures from Europe and the Mediterranean. This has led to a great deal of speculation about their origins but no conclusive answer has yet been found.
The ancient genetic data generated by Liverpool John Moores University researcher Dr. Linus Girdland-Flink and colleagues have now resolved some of the outstanding questions.
“Previous studies on the Guanches relied on single genetic markers, such as mitochondrial DNA and Y-chromosomes. These markers often lack the analytical precision needed to resolve finer levels of population history,” Dr. Girdland-Flink said.
“By sequencing autosomal DNA we gained unique insights to the ancestry and origin of these populations.”
The researchers generated the 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 for population genomic analysis.
The Guanches analyzed by the team carried mitochondrial lineages such as J1c3, H2a, U6b, L3b1a, and T2c1d2 that are common across West Eurasia and/or North Africa.
Two individuals from Tenerife and one from Gran Canaria carried the U6b1a haplotype, which is hypothesized to be endemic to and a founder lineage of the Canary Islands.
The authors also found the H1cf haplotype in one individual from Tenerife.
The three males from whom haplogroup-defining Y chromosome SNPs were retrieved carried the E1b1b1b1a1 (E-M183) haplotype. This haplogroup is ubiquitous across modern North African populations and particularly common in Berber-speaking populations of North Africa.
“By generating the first autosomal genetic data from these populations we can conclusively demonstrate that the Guanches were most closely related to modern North Africans of Berber ancestry than to any other population we included for comparisons, supporting previous studies but adding more detail and nuance,” said first author Dr. Ricardo Rodríguez Varela, a researcher at Stockholm University.
“This study gives us a fascinating insight into this unique population and we’re delighted to see our collections being used to make such an important contribution to research,” said co-author Professor Tom Gillingwater, from the University of Edinburgh.
Surprisingly, one Guanche individual carried a greater proportion of hunter-gatherer-like ancestry than the other individuals, possibly suggesting low-level gene flow from a European source that predates the European conquest.
“This type of genetic ancestry was introduced to Europe from Anatolia with migrating farmers during the Neolithic expansion around 7,000 years ago. Other North African populations have varying proportions of this ancestry but it is not yet fully understood how and when it spread across North Africa,” said co-author Professor Anders Götherström, of Stockholm University.
The scientists were also able to provide new insights to the genetic legacy of the Guanches in modern Canary Islanders.
“Our analyses show that modern inhabitants of Gran Canaria inherited circa 16-31% of their genomic ancestry from the Guanches,” said co-author Dr. Torsten Günther, from Uppsala University.
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Ricardo Rodríguez-Varela et al. Genomic Analyses of Pre-European Conquest Human Remains from the Canary Islands Reveal Close Affinity to Modern North Africans. Current Biology, published online October 26, 2017; doi: 10.1016/j.cub.2017.09.059
