Western Hunter-Gatherer

In archaeogenetics, the term Western Hunter-Gatherer, West European Hunter-Gatherer or Western European Hunter-Gatherer, is the name given to a distinct ancestral component that represents descent from Mesolithic hunter-gatherers of Western, Southern and Central Europe. The term is often abbreviated as WHG. During the Mesolithic, the WHGs inhabited an area stretching from the British Isles in the west to the Carpathians in the east.[1]

The Cheddar Man, found in Great Britain, was found to have Western Hunter-Gatherer genes.

Along with Scandinavian Hunter-Gatherers (SHG) and Eastern Hunter-Gatherers (EHG), the WHGs constituted one of the three main genetic groups in the postglacial period of early Holocene Europe.[2] The border between WHGs and EHGs ran roughly from the lower Danube, northward along the western forests of the Dnieper towards the western Baltic Sea.[1]

SHGs were in turn an equal mix of WHGs and EHGs. Once widely dispersed throughout Europe, the WHGs were largely displaced by successive expansions of Early European Farmers (EEFs) during the early Neolithic, but experienced a male-driven resurgence during the Middle Neolithic. During the Late Neolithic and Early Bronze Age, Western Steppe Herders (WSHs) from the Pontic-Caspian steppe embarked on a massive expansion, which further displaced the WHGs. Among modern-day populations, WHG ancestry is most common among populations of the eastern Baltic.

Research

Western Hunter-Gatherers (WHG) were identified as a distinct ancestral component in a study published in Nature in 2014. They were found to have contributed ancestry to all modern Europeans, including Early European Farmers (EEF), who were however mostly of Near Eastern descent. It was suggested that WHGs separated from eastern Eurasians around 40,000 BC, and from Ancient North Eurasians (ANE) around 22,000 BC.[3]

A genetic study published in Nature in June 2015 found that WHG ancestry in Western Europe had a resurgence from the Early Neolithic to the Middle Neolithic.[4]

A genetic study published in Nature in November 2015 found that most Europeans could be modeled as a mixture of WHG, EEF and peoples from the Yamnaya culture of the Pontic-Caspian steppe.[5]

A genetic study published in Nature in July 2016 found that WHGs were a mix of Eastern Hunter-Gatherers (EHGs) and the Upper Paleolithic people (Cro-Magnon) of the Grotte du Bichon in Switzerland. EHGs in turn derived 75% of their ancestry from ANEs. Scandinavian Hunter-Gatherers (SHGs) were found to be a mix of EHGs and WHGs.[lower-alpha 1]

A 2017 genetic study published in Current Biology in February 2017 determined that the people of the Mesolithic Kunda culture and the Narva culture of the eastern Baltic were a mix of WHG and EHG, showing the closest affinity with WHG. Samples from the Ukrainian Mesolithic and Neolithic were found to cluster tightly together between WHG and EHG, suggesting genetic continuity in the Dnieper Rapids for a period of 4,000 years. The Ukrainian samples belonged exclusively to the maternal haplogroup U, which is found in around 80% of all European hunter-gatherer samples.[7]

A genetic study published in Current Biology in July 2017 found that people of the Pit–Comb Ware culture (CCC) of the eastern Baltic were closely related to EHG, unlike earlier hunter-gatherers in the area, who were more closely related to WHG.[8]

A genetic study published in PLOS Biology in January 2018 analyzed 13 SHGs and found all of them to be of WHG ancestry. SHGs from western and northern Scandinavia had less WHG ancestry (ca 51%) than individuals from eastern Scandinavia (ca. 62%). The authors of the study suggested that the SHGs were a mix of WHGs who had migrated into Scandinavia from the south, and EHGs who had later migrated into Scandinavia from the northeast along the Norwegian coast. The WHGs who entered Scandinavia are believed to have belonged to the Ahrensburg culture. EHGs and WHGs displayed lower allele frequencies of SLC45A2 and SLC24A5, which cause depigmentation, and OCA/Herc2, which causes light eye color, than SHGs.[9]

In a genetic study published in Nature Communications in January 2018 found that members of the Kunda culture and Narva culture were closely related with WHG, while the Pit–Comb Ware culture was more closely related to EHG. Southern areas of the eastern Baltic were found to be more closely related to WHG than northern and eastern areas. Unlike most WHGs, the WHGs of the eastern Baltic did not receive European farmer admixture during the Neolithic. Modern populations of the eastern Baltic thus harbors a larger amount of WHG ancestry than any other population in Europe.[10]

The Genomic History of Southeastern Europe

A study published in Nature in February 2018 included an analysis of a large number of individuals of prehistoric Europe. The remains of eleven WHGs from the Upper Palaeolithic and Mesolithic in Western Europe, Central Europe and the Balkans was analyzed. Of the nine samples of Y-DNA extracted, six belonged to I haplotypes (particularly subclades of I2a), one belonged to C1a2, one belonged to R, and one possibly belonged to J. Of the eleven samples of mtDNA extracted, nine belonged to U51b haplotypes, one belonged to U5a2c, and one belonged to an U2 haplotype. These results suggested that WHGs were once widely distributed from the Atlantic coast in the West, to Sicily in the South, to the Balkans in the Southeast, for more than six thousand years.[11]

The study also 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, although WHG ancestry in this population increased during the Neolithic. Samples of Y-DNA extracted from these individuals belonged exclusively to R haplotypes (particularly subclades of R1b1) and I haplotypes (particularly subclades of I2). mtDNA belonged almost exclusively to U (particularly subclades of U5 and U4).[11]

A large number of individuals from the Zvejnieki burial ground, which mostly belonged to the Kunda culture and Narva culture in the eastern Baltic, were analyzed. These individuals were mostly of WHG descent in the earlier phases, but over time EHG ancestry became predominant. The Y-DNA of this site belonged almost exclusively to haplotypes of haplogroup R1b1a1a and I2a1. The mtDNA belonged exclusively to haplogroup U (particularly subclades of U2, U4 and U5).[11]

Forty individuals from three sites of the Iron Gates Mesolithic in the Balkans were also analyzed. These individuals were estimated to be of 85% WHG and 15% EHG descent. The males at these sites carried exclusively haplogroup R1b1a and I (mostly subclades of I2a) haplotypes. mtDNA belonged mostly to U (particularly subclades of U5 and U4).[11]

People of the Balkan Neolithic were found to harbor 98% Anatolian ancestry and 2% WGH ancestry. By the Chalcolithic, people of the Cucuteni–Trypillia culture were found to harbor about 20% hunter-gatherer ancestry, which was intermediate between EHG and WHG. People of the Globular Amphora culture were found to harbor ca. 25% WHG ancestry, which is significantly higher than Middle Neolithic groups of Central Europe.[11]

Physical appearance

It has been suggested that WHGs had dark skin and blue eyes.[9] However, Mesolithic hunter-gatherers of the eastern Baltic, who were mostly of WHG ancestry, display high frequencies of the derived alleles for SLC45A2 and SLC24A5, which code for light skin.[lower-alpha 2] YDNA haplogroups X and U predominated Ice Age Europe, both had darker pigmentations but by 10,000 a lighter eye trait had spread in them. Baltic populations descended from I1 YDNA carriers became blue eyed and light haired around 6-10,000 years ago. All modern blue eyed people have this Paleo Baltic ancestors but the light eyed(?) “Continental HGs” with darker general pigmentation died out.

Notes
  1. 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.[6]
  2. "Despite their geographical vicinity to EHG, the two Eastern Baltic individuals associated with the Mesolithic Kunda Culture show a very close affinity to WHG in all our analyses... Similar to other European Mesolithic hunter-gatherers, our Baltic foragers carry a high frequency of the derived HERC2 allele which codes for light iris colour, and like SHG and EHG they already possess an increased frequency of the derived alleles for SLC45A2 and SLC24A5, coding for lighter skin colour."[10]

References
  1. Anthony 2019b, p. 28.
  2. Kashuba 2019: "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."
  3. Lazaridis 2014.
  4. Haak 2015.
  5. Mathieson 2015.
  6. Laziridis 2016.
  7. Jones 2017.
  8. Saag 2017.
  9. Günther 2018.
  10. Mittnik 2018.
  11. Mathieson 2018.

Bibliography
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