On the origins of American Criollo pigs: A common genetic background with a lasting Iberian signature.

Maria Antonia Revidatti,María Inés Carolino,Juan Vicente Delgado,Juan Sebastian Cappello Villada,Oscar Cortés Gardyn,Luis T Gama,Antonio P Vicente,Pilar Zaragoza,Inmaculada Martin Burriel,Catarina Ginja,Philip Sponenberg,Francisco Javier Cañón,Amparo Martínez,Tzen-Yuh Chiang

doi:10.1371/journal.pone.0251879

Abstract

American Criollo pigs are thought to descend mainly from those imported from the Iberian Peninsula starting in the late 15th century. Criollo pigs subsequently expanded throughout the Americas, adapting to very diverse environments, and possibly receiving influences from other origins. With the intensification of agriculture in the mid-20th century, cosmopolitan breeds largely replaced Criollo pigs, and the few remaining are mostly maintained by rural communities in marginal areas where they still play an important socio-economic and cultural role. In this study, we used 24 microsatellite markers in samples from 1715 pigs representing 46 breeds with worldwide distribution, including 17 American Criollo breeds, with the major focus of investigating their genetic diversity, structure and breed relationships. We also included representatives of the Iberian, Local British, Hungarian, Chinese and Commercial breeds, as well as Wild Boar, in order to investigate their possible influence in the genetic composition of Criollos. Our results show that, when compared with the other breeds, Criollo pigs present higher levels of genetic diversity, both in terms of allelic diversity and expected heterozygosity. The various analyses indicate that breed differentiation overall explains nearly 21% of the total genetic diversity. Criollo breeds showed their own identity and shared a common genetic background, tending to cluster together in various analyses, even though they differ from each other. A close relationship of Criollos with Iberian breeds was revealed by all the different analyses, and the contribution of Iberian breeds, particularly of the Celtic breeds, is still present in various Criollo breeds. No influence of Chinese breeds was detected on Criollos, but a few were influenced by Commercial breeds or by wild pigs. Our results confirm the uniqueness of American Criollo pigs and the role that Iberian breeds have played in their development.

Highlights

The first domestic swine arriving in the American continent came from the Canary Islands, in the second voyage of Columbus in 1493 [1]
Criollo pigs are mostly maintained by rural communities in marginal areas, where village pigs are usually kept in a commensal relationship where they play an important role in sustainable economies by using local feed resources and converting domestic waste into animal protein [9]
The deficit in heterozygosity computed within each breed-group was significant in all breed-groups (p

Summary

Introduction

The first domestic swine arriving in the American continent came from the Canary Islands, in the second voyage of Columbus in 1493 [1]. As happened with other livestock species in the Americas, the descendants of pigs of Iberian ancestry are known as “Creole” or “Criollos”[5, 6], and they include a wide variety of populations with different phenotypic characteristics and adapted to an enormous variety of environments and production systems, spreading from the United States to Argentina, and from tropical climates to nearly desert conditions [7]. The intricacies of the American colonization process and the result of nearly 500 years of adaptation to distinct environmental conditions have contributed to the highly heterogeneous genetic pool currently represented by Criollo pigs. Criollo pigs are mostly maintained by rural communities in marginal areas, where village pigs are usually kept in a commensal relationship where they play an important role in sustainable economies by using local feed resources and converting domestic waste into animal protein [9]

Methods

Results

Discussion

Conclusion