The research team interrogated 3,600 year-old samples found in a Xiaohe cemetery in a bid to study the history of fermented dairy, from the cultures (strains) still traceable through DNA analysis to the likely route of kefir from Asia into Europe.
Based on their findings, the researchers discovered that the Xiaohe was using a breed of goats for dairying that were widespread in Eurasia during the post-Neolithic era.
Using DNA material from an ancient remnant of kefir cheese found in a tomb, researchers then examined compared ancient and modern Lactobacillus strains in order to track the arrival of kefir into Europe.
The researchers found that strains from East Asia, Tibet and the ancient Xiaohe strains they reconstructed clustered in one subspecies clade, while strains from Europe, coastal East Asia and the Pacific island were clustered into another clade.
The researchers then used the phylogeny of the ancient and modern strains to trach the spread of kefir, discovering that the spread of the ancient clade fitted the route from the Northern Caucasus mountain region in Russia to Europe – but that the other clade suggested another spreading route: from Xinjiang to other regions in inland East Asia, such as Tibet.
The research team also found that ancient cheesemaking likely shaped the evolution of the Lactobacillus species that play a major role in fermentation.
In addition, the study discovered how L. kefiranofacients, a probiotic bacteria, had evolved, including its ability to adapt to environmental stress and ecological niches.
Source:
Bronze Age cheese reveals human-Lactobacillus interactions over evolutionary history
Qiaomei Fu, et al
Published: September 25, 2024, Elsevier Inc.
DOI: 10.1016/j.cell.2024.08.008