Small ruminants are suited to a wide variety of habitats and thus represent promising study models for identifying genes underlying adaptations. Here, we considered local Mediterranean breeds of goats (n = 17) and sheep (n = 25) from Italy, France and Spain. Based on historical archives, we selected the breeds potentially most linked to a territory and defined their original cradle (i.e., the geographical area in which the breed has emerged), including transhumant pastoral areas. We then used the programs PCAdapt and LFMM to identify signatures of artificial and environmental selection. Considering cradles instead of current GPS coordinates resulted in a greater number of signatures identified by the LFMM analysis. The results, combined with a systematic literature review, revealed a set of genes with potentially key adaptive roles in relation to the gradient of aridity and altitude. Some of these genes have been previously implicated in lipid metabolism (SUCLG2, BMP2), hypoxia stress/lung function (BMPR2), seasonal patterns (SOX2, DPH6) or neuronal function (TRPC4, TRPC6). Selection signatures involving the PCDH9 and KLH1 genes, as well as NBEA/NBEAL1, were identified in both species and thus could play an important adaptive role.

Sheep and goats were among the first mammalian livestock species to be domesticated, in a process that started at ca. 10,000-9500 B.P. in Mesopotamia 1 . The subsequent expansion across the Mediterranean Basin via maritime transport included different waves of colonization. The remains testifying to these founding periods along the northern coasts of the western Mediterranean are dated from 8100 to 7700 B.P. 2 .

Waves of dispersal, which have dispatched small groups of individuals (founder effect) to very diverse habitats, are the starting point of the process that led to the emergence of breeds 3 . Traditional pastoralism, characterized by limited human intervention (i.e., "soft" artificial selection 4 ), and in conjunction with a strong influence of natural selection, led over the millennia to populations genetically differentiated and adapted to various agroclimatic conditions 5 . Sheep and goats provide an interesting model for deepening our knowledge of adaptive mechanisms under extreme environmental conditions.

In industrialized countries, artificial breeding has intensified over the past 200 years 4 , focusing mainly on agronomic traits related to milk, meat production and fiber quality. Many breeds have experienced negative impacts on their ability to adapt, their level of hardiness and sometimes their fitness by crossbreeding and/or intensive artificial selection 4, 6 . In contrast, the so-called local breeds have remained at least partially, connected to their original environments. We suggest it is among these local breeds that selection signatures related to environmental adaptation will be most detectable. For example, studies on local sheep in Ethiopia 7 and Tibet 8, 9 have identified OPEN