Scandinavian Hunter-Gatherer

In archaeogenetics, the term Scandinavian Hunter-Gatherer (SHG) is the name given to a distinct ancestral component that represents descent from Mesolithic hunter-gatherers of Scandinavia.[lower-alpha 1][2] Genetic studies suggest that the SHGs were a mix of Western Hunter-Gatherers (WHGs) initially populating Scandinavia from the south during the Holocene, and Eastern Hunter-Gatherers (EHGs), who later entered Scandinavia from the north along the Norwegian coast. During the Neolithic, they admixed further with Early European Farmers (EEFs) and Western Steppe Herders (WSHs). Genetic continuity has been detected between the SHGs and members of the Pitted Ware culture (PWC), and to a certain degree, between SHGs and modern northern Europeans.[lower-alpha 2] The Sami people, on the other hand, have been found to be completely unrelated to PWC.[lower-alpha 3]

Research

Scandinavian Hunter-Gatherers (SHG) were identified as a distinct ancestral component in a study published in Nature in 2014. A number of remains examined at Motala, Sweden, and a separate group of remains from 5,000 year-old hunter-gatherers of the Pitted Ware culture (PWC), were identified as belonging to SHG. An SHG individual from Motala was identified as being of 81% Western Hunter-Gatherer (WHG) ancestry, and 19% Ancient North Eurasian (ANE) ancestry.[5]

In a genetic study published in Nature in March 2015, the remains of six SHGs buried at Motala between ca. 6000 BC and 5700 BC. Of the four males surveyed, three carried the paternal haplogroup I2a1 or various subclades of it, while the other carried I2c. With regard to mtDNA, four individuals carried subclades of U5a, while two carried U2e1. The study found SHGs to constitute one of the three main hunter-gatherer populations of Europe during the Holocene.[lower-alpha 4][lower-alpha 5] The two other groups were WHGs and EHGs (Eastern Hunter-Gatherers), between whom SHGs formed a distinct cluster. SHGs living between 6000 BC and 3000 BC were found to largely genetically homogenous, with little admixture occurring among them during this period. EHGs were found to be more closely related to SHGs than WHGs.[6]

In a genetic study published in Nature in November 2015, the six SHGs from Motala were subjected to further analysis. The study found it possible to model SHGs as a mixture of WHGs and EHGs. SHGs appeared to have persisted in Scandinavia until after 5,000 years ago. Results from studies of SHGs were found to be surprising. The Motala SHGs were found to be closely related to WHGs. In three samples, the haplotype carried the derived allele of rs3827760 in the EDAR gene, which is today common in East Asia, but largely absent in modern-day Europe outside Scandinavia. This haplotype is not of East Asian origin however. Most of the Motala SHGs were found to have the depigmentation alleles SLC45A2 and SLC24A5.[7]

A genetic study published in Nature in July 2016 found SHGs to be a mix of EHGs and WHGs. WHGs were in turn a mix of EHGs and the Upper Paleolithic people (Cro-Magnon) of the Grotte du Bichon in Switzerland. EHGs derived 75% of their ancestry from ANEs.[lower-alpha 6]

In a genetic study published in PLOS Biology in January 2018, the remains of seven SHGs were examined. All three samples of Y-DNA extracted belonged to subclades of I2. With respects to mtDNA, four samples belonged to U5a1 haplotypes, while three samples belonged U4a2 haplotypes. All samples from western and northern Scandinavia carried U5a1 haplotypes, while all the samples from eastern Scandinavia except from one carried U4a2 haplotypes. The authors of the study suggested that SHGs were descended from a WHG population that had entered Scandinavia from the south, and an EHG population which had entered Scandinavia from the northeast along the coast. The WHGs who entered Scandinavia are believed to have belonged to the Ahrensburg culture. These WHGs and EHGs had subsequently mixed, and the SHGs gradually developed their distinct character. The SHGs from western and northern Scandinavia had less more EHG ancestry (ca 49%) than individuals from eastern Scandinavia (ca. 38%). The SHGs were found to have a genetic adaption to high latitude environments, including high frequencies of low pigmentation variants and genes designed for adaption to the cold and physical performance. SHGs displayed a high frequency of the depigmentation alleles SLC45A2 and SLC24A5, and the OCA/Herc2, which effects eye pigmentation. These genes were much less common among WHGs and EHGs. A surprising continuity was displayed between SHGs and modern populations of Northern Europe in certain respects. Most notably, the presence of the protein TMEM131 among SHGs and modern Northern Europeans was detected. This protein may be involved in long-term adaptation to the cold.[3]

In a genetic study published in Nature Communications in January 2018, the remains of an SHG female at Motala, Sweden between 5750 BC and 5650 BC was analyzed. She was found to be carrying U5a2d and "substantial ANE ancestry". The study found that Mesolithic hunter-gatherers of the eastern Baltic also carried high frequencies of the HERC2, SLC45A2 and SLC24A5 alleles. They however harbored less EHG ancestry than SHGs. Genetic continuity between the SHGs and the Pitted Ware culture of the Neolithic was detected. The results further underpinned previous suggestion that SHGs were descended from northward migration of WHGs and a subsequent southward migration of EHGs.[9] A certain degree of continuity between SHGs and northern Europeans was detected.[lower-alpha 2]

A study published in Nature in February 2018 included an analysis of a large number of individuals of prehistoric Eastern Europe. Thirty-seven samples were collected from Mesolithic and Neolithic Ukraine (9500-6000 BC). These were determined to be an intermediate between EHG and SHG. Samples of Y-DNA extracted from these individuals belonged exclusively to R haplotypes (particularly subclades of R1b1 and R1a)) and I haplotypes (particularly subclades of I2). mtDNA belonged almost exclusively to U (particularly subclades of U5 and U4).[10]

Physical appearance

Genomic data suggest that SHGs had slightly darker skin than EHGs but lighter skin than WHGs and blue to light brown eye color. This is strikingly different from WHGs and EHGs, who are believed to have been blue eyed and dark skinned, and brown-eyed and light-skinned, respectively.[3] On the basis of archaeological and genetic evidence, the Swedish archaeologist Odin Nilsson has made forensic reconstructions of both male and female SHGs.[11][12][13]

See also

Notes
  1. "Earlier aDNA studies suggest the presence of three genetic groups in early postglacial Europe: Western hunter–gatherers (WHG), Eastern hunter–gatherers (EHG), and Scandinavian hunter–gatherers (SHG)4. The SHG have been modelled as a mixture of WHG and EHG."[1]
  2. "Modern-day northern Europeans trace limited amounts of genetic material back to the SHGs."[3]
  3. "Population continuity between the PWC and modern Saami can be rejected under all assumed ancestral population size combinations."[4]
  4. "We can discern three different groups of hunter-gatherers who lived in Europe before the arrival of the first farmers: western European hunter-gatherers (WHG) in Spain, Luxembourg, and Hungary; eastern European hunter-gatherers (EHG) in Russia, and Scandinavian huntergatherers (SHG) in Sweden."[6]
  5. "[T]he three main groups of Holocene hunter-gatherers (WHG, EHG, SHG)."[6]
  6. Eastern Hunter Gatherers (EHG) derive 3/4 of their ancestry from the ANE […] Scandinavian hunter-gatherers (SHG) are a mix of EHG and WHG; and WHG are a mix of EHG and the Upper Paleolithic Bichon from Switzerland.[8]

References
  1. Kashuba 2019.
  2. Eisenmann 2018.
  3. Günther 2018.
  4. Malmström 2009.
  5. Lazaridis 2014.
  6. Haak 2015.
  7. Mathieson 2015.
  8. Lazaridis 2016.
  9. Mittnik 2018.
  10. Mathieson 2018.
  11. Romey 2019.
  12. Romey 2020.
  13. Nilsson 2020, The Tybrind girl.

Bibliography

Further reading
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