Palaeoproteomic and genetic insights into millennial-scale dairy consumption in Armenia

Dairy products are a key component of the diet in Armenia today, yet the origins of milk consumption, its historical development, and genetic adaptations related to milk digestion in the region remain understudied. Here, we investigate the co-evolution of dairying practices and lactase persistence in Armenia through combined palaeoproteomic and genetic analyses spanning from prehistory to the present. Our palaeoproteomic results provide direct evidence for milk consumption in prehistoric Armenia and, in conjunction with existing regional data, indicate that dairying was an established component of the South Caucasus subsistence economy from at least the late fourth millennium BCE. We found evidence of milk consumption from multiple species across archaeological periods, with cattle milk representing the earliest confirmed evidence from the Chalcolithic period. Notably, milk proteins were predominantly recovered from high-altitude sites, suggesting that dairy consumption served as an adaptive strategy for harsh highland environmental conditions. In contrast to the widespread evidence for milk consumption, our genetic findings indicate that the lactase persistence-associated variants never reached high frequencies throughout Armenian prehistory. This pattern suggests that the relatively low frequency of lactase persistence may reflect a predominant cultural adaptation to the fermentation of dairy products, which reduces lactose content and enables dairy use even in genetically lactose-intolerant populations.