The Vikings played a preeminent role in the peopling of the North Atlantic, and one might expect populations that were founded by them to be genetically similar and homogeneous. New research suggests that the Icelandic and Faroese populations had distinguishably different founding fathers. The results are consistent with the scenario that the Faroese male population was founded by a more diverse group from divergent Scandinavian populations than their Icelandic neighbors. Furthermore, the study conclusively demonstrates that there is no evidence for post-founder admixture between the Faroese and Icelandic gene pools.
The Faroe Islands consist of an archipelago of 18 small islands, located in the North Atlantic, between South Norway, Iceland and Scotland. As a result of their demographic history and relative geographic isolation, the Faroe Islands, along with other North Atlantic Island populations, are genetically homogenous as compared to mainland populations. Historical and archaeological sources report that the Faroe Islands were settled around 800 CE by Vikings largely from western Norway. However, a growing body of evidence suggests that the islands were settled prior to this time, possibly by Celtic monks or other persons originating from the British Isles. Carbon dating of peat moss and barley grains support two pre-Viking settlement phases, around 300-500 CE and 500-700 CE. More recently, scientists detected sheep-DNA in archaeological sediments from 500 CE, and based on modern whole-genome data, they estimated that the initial founding of the Faroe Islands occurred between 50 and 300 CE, potentially two to three centuries earlier than previously believed based on archaeological findings alone. Image credit: Oscar C.R.
Between 8th century and approximately 1050 CE, the Vikings roamed the Atlantic in their longships all the way to Newfoundland, Labrador, and Greenland, as well as exploring the Mediterranean and continental Eurasia.
Among the places they are known to have settled were the Faroe Islands, an archipelago of 18 islands in the North Atlantic.
They probably weren’t the first to do so: archaeologists have found evidence that these islands had been inhabited since approximately 300 CE, possibly by Celtic monks or others from the British Isles.
But according to the Færeyinga Saga, written around 1200, a Viking chief called Grímur Kamban settled in the Faroe Islands between approximately 872 and 930 CE. But where in Scandinavia did Grímur and his followers come from?
“Here we provide strong evidence that the Faroe Islands were colonized by a diverse group of male settlers from multiple Scandinavian populations,” said Dr. Christopher Tillquist, a researcher at the University of Louisville.
In the study, Dr. Tillquist and his colleagues determined the genotype at 12 ‘short tandem repeat’ (STR) loci on the Y-chromosome of 139 men from the Faroese islands of Borðoy, Streymoy, and Suðuroy.
They assigned each man to the most likely haplogroup, each of which has different known distribution across today’s Europe.
They compared the distribution of genotypes to those found in 412 men from Norway, Sweden, Denmark, Iceland, and Ireland.
This allowed the team to reconstruct the source population of the Viking population founders.
Advanced analyses showed that the range of Faroese samples resembled the range of genotypes from broader Scandinavian, whereas the Icelandic genotypes where distinct.
The authors also developed a powerful innovative genetic method, called ‘Mutational Distance from Modal Haplotype’ to analyze variation in SNPs (single-nucleotide polymorphisms) within the STRs.
This allowed them to reveal a ‘founder effect’ — traces of random loss of diversity during historic colonization by a small number of people — persisting in the genetic make-up of today’s Faroese and Icelandic male populations.
“Scientists have long assumed that the Faroe Islands and Iceland were both settled by similar Norse people,” Dr. Tillquist said.
“Yet our novel analysis has shown that these islands were founded by men from different gene pools within Scandinavia.”
“One group, diverse in their Scandinavian origins, established themselves in the Faroe Islands, while another and more genetically divergent band of Vikings colonized Iceland. They have separate genetic signatures that persist to this day.”
“There doesn’t seem to have been any interbreeding afterwards between these two populations, despite their geographic proximity.”
“Our results demonstrate that Viking expansion into the North Atlantic was more complex than previously thought.”
“Each longship that set sail for these distant islands carried not just Vikings, but distinct genetic legacies.”
“We can now trace these separate journeys of conquest and settlement, revealing a more nuanced story of Viking exploration than told by the history books.”
The findings appear in the journal Frontiers in Genetics.
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Allison E. Mann et al. 2024. Genetic evidence points to distinct paternal settlers of the Faroe Islands and Iceland. Front. Genet 15; doi: 10.3389/fgene.2024.1462736
Source : Breaking Science News