January 15-19, 2011
Town & Country Convention Center
San Diego, CA
Oriol Timoneda1 , Ingrid Balcells1 , Sara Collins1 , Gonzalo Vera2 , Raquel Egea2 , Anna Castelló1 , José Ignacio Núñez3 , Anna Tomàs1 , Armand Sanchez1
MicroRNAs (miRNAs) are a new important class of posttranscriptional regulators in mammals targeting mRNAs and repressing their functions. The uncertain process of swine domestication, with different origin focuses, and the selection process that commercial breeds suffered, have generated a wide spectrum of breeds with clear genetic and phenotypic variability. This work defines the miRNAs profile in kidney of several porcine breeds and determines whether there are differences in miRNA expression between them that could add a new layer of complexity to the interesting process of pig evolution. Small RNA libraries were elaborated using pooled kidney samples (2-4 animals) from 7 different geographical origins, including European Wild Boar and Iberian, the European commercial breeds Landrace, Large White and Piétrain, and the Asiatic Vietnamese and Meishan breeds. Small RNA libraries were sequenced using a 454 GSFLX (Roche). The swine kidney microRNAome included 154 out of the 211 known swine miRNAs and other 227 orthologous miRNAs not yet described in pigs. Preliminary studies revealed 77 miRNAs differentially expressed among breeds. Expression levels of 17 miRNAs were validated through qRT-PCR with miRCURY LNATM probes (Exiqon). Significant differential expression (p-value<0.05) between breeds was confirmed for some miRNAs, such as miR-200b or miR-16b which were over and under expressed in European Wild Boar and Iberian breeds, respectively, whereas miR-126, miR-126* and miR-99 were less expressed in Asian breeds. The identification of breed-specific miRNAs, which could be potentially associated to certain phenotypes, will become a new tool for the study of the genetic variability underlying complex traits.