Genetic Diversity and Structure of Iberoamerican Livestock Breeds

Creole breeds of the various livestock species mainly derive from animals imported to America from the Iberian Peninsula, starting in the early years of discovery and colonization. Creoles have undergone a long period of selective adaptation to a diverse set of environmental conditions in the Americas, and over the last two centuries some Creole populations were admixed with breeds from other European countries and from India. In spite of various threats, some Creole populations are still maintained nowadays, especially in marginal regions, but they need to be better known, in order to recognize their identity and establish conservation programs. Here, we review the results published over the last years by various Consortia established under the framework of the CONBIAND network, with the goal of studying the genetic diversity, structure and breed relationships in Creole breeds. Overall, Creole breeds reveal high levels of genetic diversity and signatures of Iberian origin, but many breeds also show signs of genetic erosion, due to inbreeding or admixture with exotic breeds. The vast majority of Creoles still maintain their own identity, and these results can be used as a basis for recognition, conservation and genetic improvement of Creoles, which result from over 500 years of selective adaptation.