The Genomic Landscape of the Western Hunter-Gatherers

The genetic makeup of modern Europeans is the result of a complex mixing of three ancient populations: Early European Farmers (EEF), Western Steppe Herders (WSH), and the Western Hunter-Gatherers (WHG). Emerging from southern ecological refuges after the Last Glacial Maximum (around 14,000 years ago), the WHG represent the oldest indigenous layer of the European Holocene gene pool. Rather than being entirely wiped out by incoming agriculturalists, their genetic legacy was intricately woven into subsequent populations through complex patterns of interbreeding and natural selection.

Paleogenomics reveals that the WHG possessed a physical appearance rarely seen today: a striking combination of deeply pigmented dark skin, dark hair, and bright blue eyes. Because their forager diet of meat and fish was naturally rich in Vitamin D, they didn't face the evolutionary pressure to develop the light skin needed to absorb sunlight in northern latitudes. The genetic mutation for blue eyes, however, was universally present among them, likely driven to fixation by small population bottlenecks or sexual selection.

When Early European Farmers arrived from Anatolia around 8,500 years ago, they initially displaced the WHG. However, over millennia, a "resurgence" occurred as farmers expanded into forested and less hospitable territories. This integration was heavily sex-biased. While early farming communities were distinctly patrilocal, the male descendants of the hunter-gatherers—carrying Y-chromosome Haplogroup I—eventually integrated into and dominated the paternal lineages of these admixed agricultural societies.

The collision of these two populations triggered intense natural selection. The WHG had spent millennia adapting to local European pathogens and passed on crucial immune system adaptations (specifically at the MHC locus) that helped early farmers survive newly encountered zoonotic diseases. Conversely, the WHG descendants adopted farmer genes for light skin to survive agrarian diets lacking in natural Vitamin D. Today, the metabolic traits of the WHG—optimized for a high-protein, low-carbohydrate foraging lifestyle—contribute significantly to modern genetic risks for Type 2 Diabetes and late-onset Alzheimer's disease.

While WHG DNA forms a basal layer across all of Europe, its modern distribution is highly uneven. Southern Europeans retain the least, heavily dominated by Early European Farmer ancestry. The highest concentrations of WHG DNA in the world are found in the Eastern Baltic (Lithuania, Latvia, and Estonia), where dense forests and a delayed transition to agriculture allowed hunter-gatherer genetics to persist in isolation much longer than in the rest of the continent.

Видео The Genomic Landscape of the Western Hunter-Gatherers канала Anthromedia