Population genomics of the Viking world

Abstract

87 The Viking maritime expansion from Scandinavia (Denmark, Norway, and Sweden) marks one 88 of the swiftest and most far-flung cultural transformations in global history. During this time 89 (c. 750 to 1050 CE), the Vikings reached most of western Eurasia, Greenland, and North 90 America, and left a cultural legacy that persists till today. To understand the genetic structure 91 and influence of the Viking expansion, we sequenced the genomes of 442 ancient humans from 92 across Europe and Greenland ranging from the Bronze Age (c. 2400 BC) to the early Modern 93 period (c. 1600 CE), with particular emphasis on the Viking Age. We find that the period 94 preceding the Viking Age was accompanied by foreign gene flow into Scandinavia from the 95 south and east: spreading from Denmark and eastern Sweden to the rest of Scandinavia. 96Despite the close linguistic similarities of modern Scandinavian languages, we observe genetic 97 structure within Scandinavia, suggesting that regional population differences were already 98 present 1,000 years ago. We find evidence for a majority of Danish Viking presence in England, 99 Swedish Viking presence in the Baltic, and Norwegian Viking presence in Ireland, Iceland, and 100Greenland. Additionally, we see substantial foreign European ancestry entering Scandinavia 101 during the Viking Age. We also find that several of the members of the only archaeologically 102 well-attested Viking expedition were close family members. By comparing Viking Scandinavian 103 genomes with present-day Scandinavian genomes, we find that pigmentation-associated loci 104 have undergone strong population differentiation during the last millennia. Finally, we are able 105 to trace the allele frequency dynamics of positively selected loci with unprecedented detail, 106 including the lactase persistence allele and various alleles associated with the immune response. 107We conclude that the Viking diaspora was characterized by substantial foreign engagement: 108 distinct Viking populations influenced the genomic makeup of different regions of Europe, 109 while Scandinavia also experienced increased contact with the rest of the continent. 110 111

The spatiotemporal spread of human migrations during the European Holocene

“…Firstly, we are assuming that changes in ancient ancestries can be used as a proxy for long-distance movement of people. This may be the case for particular periods of time-especially when peoples of highly divergent ancestries first met each other-but this assumption loses validity as we move closer to the present and the ancestry components tend to become more homogenized due to later migrations within the area of study (56). Tracing relatively high YAM ancestry in the present day is approximately equivalent to tracing people with high Northern European ancestry, who cannot be equated with ancient "steppe peoples.…”

Increased ultra-rare variant load in an isolated Scottish population impacts exonic and regulatory regions

“…The detailed demographics and history of the Norse diaspora is still an area of active research (e.g. [57]). We look forward to deep WGS data from relevant Scandinavian populations (with compatible sequencing technologies and sample ascertainment) becoming available in the future.…”

A review of UMAP in population genetics

“…UMAP has also been successfully used with ancient DNA samples combined with modern and contemporary populations to identify shared population structure [15], as well as animal populations to study spatial introgression in mussels [16], genetic bottlenecks in the white rhino population [17], and the geographic origin of disease-carrying mosquitoes [18,19].…”