Archaeological evidence suggests that selection for woolly sheep may have begun around 6000 BC.Р”Вairy sheep are mainly found in Europe, especially in Mediterranean areas, where they have been traditionally exploited as a dual purpose species, with income from both meat and milk. Initially, sheep were kept solely for meat, milk and skins. 3 000 BC and primarily concerned morphological and coat colour traits with the initial major morphological changes including reduction in the length of the legs, lengthening of the tail and alteration of horn shape. The first documented modifications to sheep by human-imposed selection had taken place by the time that illustrations and records first appeared c. Adaptation to very different geographic and climatic conditions and the specialization for specific characteristics have resulted in a phenotypically highly diverse species. Since their domestication 8 000РІР‚вЂњ9 000 years ago (reviewed by ), sheep ( Ovis aries) have been used by humans for the production of wool, meat and milk. Due to the limited number of QTL studies reported in sheep compared with cattle, the results illustrate the potential value of selection mapping to identify genomic regions associated with dairy traits in sheep.

Few of the identified regions were coincident with QTL previously reported in sheep, although many of them corresponded to orthologous regions in cattle where QTL for dairy traits have been identified. LALBA, DGAT1A) were not associated with a detectable sweep signal. ABCG2, SPP1), whereas some other genes designated as candidates based on their association with sheep and cattle dairy traits (e.g. For some of them, strong candidate genes have been proposed (e.g. Following this approach six regions were detected. Regions detected in at least two breeds (breed pairs) by the two approaches (genetic differentiation and at least one of the heterozygosity-based analyses) were labeled as core candidate convergence regions and further investigated for candidate genes. With this aim, genotypes from 44,545 SNP markers covering the sheep autosomes were analysed in both European dairy and non-dairy sheep breeds using two approaches: (i) identification of genomic regions showing extreme genetic differentiation between each dairy breed and a closely related non-dairy breed, and (ii) identification of regions with reduced variation (heterozygosity) in the dairy breeds using two methods.

Modernization of husbandry methods and the establishment of breeding schemes focused on milk production have led to the development of РІР‚Сљdairy breeds.РІР‚Сњ This study investigated selective sweeps specifically related to dairy production in sheep by searching for regions commonly identified in different European dairy breeds. In Europe, especially in Mediterranean areas, the sheep has been traditionally exploited as a dual purpose species, with income from both meat and milk.

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