Evolution of the species Ovis aries

The sheep was one of the first domesticated animals in Neolithic Southwest Eurasia. The presented study suggests that the domestication of sheep occurred on the Anatolian plateau, to the northwest of the commonly accepted boundaries of the Fertile Crescent, rather than within it. However, many aspects of the domestication process (the specific place, time, and history after domestication) have remained not fully understood. The review examines in detail the complex origin, traces the primary role of the Asian mouflon (Ovis gmelini) as an ancestor, and also discusses controversial aspects of the contribution of other wild Ovis species. It reveals the history of the introduction and migration of sheep in the world, and summarizes the current scientific understanding of the phylogenetic relationships between populations of wild mouflons and domestic sheep (Ovis aries). A multifaceted process of domestication is considered, and the proposed evolutionary mechanisms are discussed, such as the domestication syndrome and hypotheses about thyroid hormones, as well as the human-mediated selection of key phenotypic traits. The article analyzes the results obtained using various genetic markers, including mitochondrial DNA haplogroups. Phylogenetic analysis using mitochondrial DNA has been successfully applied to identify the phylogeographic patterns and divergence times, from the early Neolithic to the Middle Ages, of sheep migration from the domestication center to Asia, Europe, and Africa. Domesticated sheep, having survived and endured extreme climate changes that occurred in the last post-glacial period, became the ancestors of modern local sheep breeds. Starting from the seventh millennium BC, domesticated sheep were brought to the Caucasus, Central Asia, and Europe. The spread of sheep in Asia began from the Middle East to the Mongolian Plateau and the Indian subcontinent, then to the north and southwest of China. In Russia, the territory of which covers a significant part of Eurasia, a unique breed diversity of sheep has been developed, with haplogroup B typical for breeds of the European-type origin (western geographic regions), and haplogroup A of the Asian-type sheep (eastern geographic regions).