Population genomics of Mesolithic Scandinavia: Investigating early postglacial migration routes and high-latitude adaptation

Abstract

Scandinavia was one of the last geographic areas in Europe to become habitable for humans after the Last Glacial Maximum (LGM). However, the routes and genetic composition of these postglacial migrants remain unclear. We sequenced the genomes, up to 57× coverage, of seven hunter-gatherers excavated across Scandinavia and dated from 9,500–6,000 years before present (BP). Surprisingly, among the Scandinavian Mesolithic individuals, the genetic data display an east–west genetic gradient that opposes the pattern seen in other parts of Mesolithic Europe. Our results suggest two different early postglacial migrations into Scandinavia: initially from the south, and later, from the northeast. The latter followed the ice-free Norwegian north Atlantic coast, along which novel and advanced pressure-blade stone-tool techniques may have spread. These two groups met and mixed in Scandinavia, creating a genetically diverse population, which shows patterns of genetic adaptation to high latitude environments. These potential adaptations include high frequencies of low pigmentation variants and a gene region associated with physical performance, which shows strong continuity into modern-day northern Europeans.

A genomic dating tool resolves the origins of ancient Eurasian genomes

“…Motivated by our observations that allele frequencies show a temporal variability over time we introduced the concept of Time 15 Informative Markers (TIMs). We showed that TIMs, like rs1393350 associated with pigmentation, have increased or decreased their frequency over time as reported elsewhere (30,37,38,40) and can be used as biomarkers for specific time periods. Based on this concept, we developed the Temporal Population Structure (TPS) tool, which utilises TIMs to date ancient skeletons as far back as the Late Upper Palaeolithic using their genomic data without prior assumptions.…”

“…TPS date for RISE174 is 4,347-3,533 BP, consistent with the Neolithic attribution of the site. 40 Correcting the radiocarbon date at Kyndeløse, Denmark. RISE61 was radiocarbon-dated to 4,801-4,442 BP (17), which is suggestive of a Middle Neolithic origin ascribed to 5,400-4,700 BP in Scandinavia.…”

“…Here, we present the Temporal Population Structure (TPS) tool, the first DNA-based dating method suitable for samples younger than 15,000 BP. Compared to radiocarbon dating, DNA 40 analyses require much less materials (x1/5) (19), which makes DNA-based dating methods more viable in case of limited materials. Thus, TPS can be used to directly date skeletal aDNA for which no radiocarbon date is available or as an independent validation approach to existing results.…”

Holocene vegetation change in northernmost Fennoscandia and the impact on prehistoric foragers 12 000–2000 cal. aBP– A review

“…; Damlien ; Günther et al . ). From the following centuries, a number of sites from the inland in both northern Finland and Norway give evidence for a more extensive use of terrestrial resources in the birch woodlands and forests (Halinen ; Hood ).…”

“…As in recent history, plants were probably of secondary importance as subsistence in prehistoric northern Fennoscandia (Günther et al . : supplement S1 text), but they might have been important for key nutrients such as vitamin C (Bergman et al . ), and a welcome culinary supplement.…”