The genetic diversity and phylogeography of Mexican domestic sheep

Domestic sheep were introduced in Mexico by the Spanish settlers in the 16th century. Nowadays, Mexico hosts several sheep breeds, adapting and evolving in both farming and traditional livestock production systems and different climate conditions. Research on the diversity of ovine genetic resources is urgently needed to prevent and reverse genetic erosion. Despite the relevance of Mexican sheep, data is still limited regarding their genetic diversity and history. We analysed the mitochondrial DNA (mtDNA) control region from different sheep breeds and municipalities of the State of Mexico, together with a large dataset of 542 sequences from America and the Iberian Peninsula. We identified a low genetic diversity in Mexican sheep, all belonging to haplogroup B. The phylogenetic analyses revealed low genetic distance among Cuba, Mexico, Portugal and Spain sheep populations, suggesting intense gene flow. Our results contribute for a better comprehension of the genetic diversity of domestic sheep in Mexico and Ibero-America.