The processes of speciation and domestication are responsible for the multiplication of life form on earth. Understanding these crucial evolutionary processes is key to unravel the origin of species. Traditionally, evolutionary biologists view speciation and domestication as the result of geographic and/or reproductive isolation of two populations into two different species. However, until recently, the lack of large-scale genetic data sets has prevented evolutionary biologists from fully grasping their complexity. This thesis focuses on investigating speciation and domestication in Suiformes (pig and related species) using large-scale genetic data (genomes). The novel approaches used in this work allowed for a revision of the concepts of speciation and domestication. More precisely, this thesis shows that speciation and domestication in Suiformes took place without reproductive or geographic isolation. Such a lack of reproductive or geographic isolation demonstrates that natural and/or artificial selection are the main phenomena that drive the diversification of Suiformes species.