Sheep have been a cornerstone of human civilization for over 11,000 years, serving not just as a source of food but also providing materials essential for survival, like wool and milk. From the pastoral landscapes of the Fertile Crescent to the windswept steppes of Eurasia, sheep have played an essential role in shaping human societies and economies. The domestication of sheep, which began in the wild mouflon populations of the Near East, is one of the most significant agricultural developments in human history.
Now, an international team of geneticists from Trinity College Dublin, along with zooarchaeologists from LMU Munich and the Bavarian State Collections of Natural History (SNSB), have embarked on a groundbreaking study to decipher the prehistoric journey of the domestic sheep. Their research, published in the prestigious journal Science, focuses on 118 ancient sheep genomes recovered from archaeological sites spanning 12 millennia, with samples taken from regions as diverse as Mongolia and Ireland.
The Genesis of Sheep Domestication
The study reveals the rich cultural and genetic history of sheep herding, starting with one of the earliest sheep-herding villages in the world—Aşıklı Höyük, located in central Türkiye. These genomes represent some of the first domesticated sheep populations, confirming the origins of sheep herding in the western regions of the northern Fertile Crescent. This area, stretching across parts of present-day Turkey, Iraq, and Syria, was a hotspot for the domestication of many key species, including sheep.
The team’s findings suggest that the domestication of sheep began over 11,000 years ago, with wild mouflon being captured and tamed by early human societies. These ancient sheep were pivotal in the development of early agriculture, providing meat, milk, and wool—resources that would support growing populations and accelerate the spread of human civilizations.
Genetic Evidence of Early Human Intervention
As the team analyzed sheep genomes from different time periods and regions, they discovered compelling evidence of human influence on sheep breeding as early as 8,000 years ago. In particular, the team identified the selective breeding of sheep for specific traits, especially the coat color. This is a key finding because it marks the earliest known example of humans intentionally selecting traits in domesticated animals, which is a practice still evident today in modern animal breeding.
The primary gene associated with this early selective breeding was the KIT gene, which is linked to the production of white coat color in livestock. By selecting sheep with this trait, early herders were likely enhancing the visual appeal of their flocks, much like modern farmers select animals for desirable traits. This discovery not only underscores the sophisticated nature of early sheep husbandry but also hints at an aesthetic preference that may have influenced the breeding practices of ancient farmers.
Genetic Divergence and Sheep Migration
By 8,000 years ago, sheep populations in Europe and regions further east, such as Iran and Central Asia, began to show significant genetic divergence. This divergence suggests that sheep populations were adapting to different climates and agricultural systems across the regions. However, this separation did not last long, as human movement and cultural expansion facilitated the migration of sheep across vast distances.
Around 7,000 years ago, in parallel with the rise of early urban centers in Mesopotamia, sheep genomes began to spread westward, moving within the Fertile Crescent. This movement of sheep mirrored the spread of human culture, as agricultural practices, including sheep herding, radiated outward from the cradle of civilization.
A more profound shift occurred 5,000 years ago, with the rise of pastoralist societies in the Eurasian steppes. These societies, particularly the Yamnaya culture in the Pontic-Caspian steppe, played a critical role in the transformation of Europe. These pastoralist people, who relied heavily on sheep herding, migrated westward, bringing with them their flocks and significantly influencing the genetic makeup of European populations.
This migration, which brought Indo-European languages to Europe, is also reflected in the genetic data of domestic sheep. By the time of the Bronze Age, sheep populations had undergone a transformation, with approximately half of their genetic ancestry originating from the Eurasian steppes. This major genetic influx highlights the significant role of sheep herding in facilitating the massive human migrations that reshaped the genetic landscape of Europe.
Sheep Herding and the Spread of Human Culture
According to Dr. Kevin Daly, the first author of the research and Assistant Professor at UCD School of Agriculture and Food Science, the results of the study reveal a fascinating parallel between the migration of humans and the movement of sheep. He noted that the genetic data suggests that, as humans migrated across the Eurasian steppes, they brought their flocks with them, leading to the spread of domestic sheep and the transformation of human societies along the way. This suggests that sheep herding was not just a mode of subsistence but also a key cultural practice that facilitated the spread of knowledge, language, and social structures.
The integration of sheep herding with the rise of pastoralist cultures helped shape the social and economic systems of these communities. The herding of sheep became a symbol of prosperity and stability, as these animals were not only a source of food and material wealth but also an important component of trade and exchange.
A Shared Legacy of Humans and Sheep
As the research by Professor Dan Bradley, leader of the study, demonstrates, the relationship between humans and sheep has evolved over thousands of years, from the domestication of the first flocks to the development of sheep as a critical resource in textiles and agriculture. Sheep wool, for example, became a crucial part of human economies, particularly in the Bronze Age, when textiles began to play an increasingly important role in trade and craftsmanship. The domestication of sheep was thus not just about food production but also about the development of a vital textile industry that would serve civilizations for millennia.
Professor Joris Peters, co-author of the study, emphasized that while this research provides a comprehensive view of the genetic history of domestic sheep, it also highlights the need for further research to better understand the dispersal and selection of the various sheep breeds that exist today across Eurasia and Africa. As modern-day farmers continue to select for specific traits in their flocks, understanding the ancient origins of these practices can help improve current breeding and conservation efforts.
Conclusion
The findings of this study offer a new lens through which we can understand the profound role of sheep in human history. From their domestication in the Fertile Crescent to their integration into the cultures of the Eurasian steppes, sheep have been far more than just livestock; they have been integral to the development of human societies and economies. By analyzing ancient genomes, this research illuminates the evolutionary journey of sheep and their deep connection to human culture, trade, and migration.
As modern science continues to explore the intricate relationship between humans and animals, this study serves as a reminder of how our ancient past continues to shape the world we live in today, with sheep remaining an enduring symbol of human ingenuity and adaptation over millennia.
Kevin G. Daly et al, Ancient genomics and the origin, dispersal, and development of domestic sheep, Science (2025). DOI: 10.1126/science.adn2094. www.science.org/doi/10.1126/science.adn2094