31Brazilian hair sheep constitute a genetic diversity hotspot of sheep breeds. These locally 32 adapted genetic resources developed in harsh environments of the Brazilian Northwest 33 (semi-arid) and maintained important traits for this region, such as parasite resistance, 34 heat tolerance and high pelt quality. Genotypes (50K SNP chip) from seven Brazilian 35 sheep breeds (5 hair and 2 coarse wool types) and 87 worldwide breeds were used to 36 verify population structure, admixture and genetic diversity, using PCA and 37 ADMIXTURE analyses. We constructed a phylogenetic tree and evaluated migration 38 events between genetic groups using TREEMIX software. Brazilian Somali, a fat-tailed 39 breed, was the unique breed with high relationship with East African breeds and formed 40 a distinct cluster from other Brazilian breeds. This breed seems to contribute to formation 41 of Santa Inês, Morada Nova and Brazilian Fat-tail breeds. Brazilian Blackbelly had a clear 42 relationship with Barbados Blackbelly, which appeared as another group. Other Brazilian 43 breeds seem to form a further genetic group with some recent admixtures. Morada Nova 44 remained as a separate group, not showing a strong relationship with European or African 45 breeds, only revealing a migration event from Sidaoun, an Algerian hair breed. Brazilian 46 Fat-tail and Morada Nova share a common ancestor, but the first received introgressions 47 from Brazilian Somali and Afrikaner breeds, explaining the fat-tail phenotype. Santa Inês 48 received strong contribution from Bergamasca and had an admixed origin with recent 49 introgressions from other breeds, mainly from Suffolk animals. In conclusion, Brazilian 50 Somali and Brazilian Fat-tail are the most endangered sheep genetic resources in Brazil.51 52 53 Cattle, sheep, goats and pigs were domesticated in the region from Central 54