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. 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. The Sami people, on the other hand, have been found to be completely unrelated to PWC.
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.
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. 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.
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.
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.
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 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.
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. A certain degree of continuity between SHGs and northern Europeans was detected.
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).
Physical appearance.
Genomic data has shown that SHGs displayed higher levels of light pigmentation variants compared to their two source populations, WHGs and EHGs. SHGs had high levels of derived allele frequencies for three pigmentation-associated SNPs ("SLC24A5", "SLC45A2", which are associated with skin depigmentation, and "OCA2/HERC2", which is associated with eye pigmentation and may contribute to a light or blonde hair colour). A study by "Günther et al, 2018", attributed this depigmentation to adaptations to cold and low light conditions.The earliest recorded individual with a combination of a blonde hair colour and a blue eye colour is a SHG from Motala. These traits have also been found in individuals from later SHG populations like the Pitted Ware culture. On the basis of archaeological and genetic evidence, the Swedish archaeologist Oscar D. Nilsson has made forensic reconstructions of both male and female SHGs.