Association of the porcine transforming growth factor beta type I receptor (TGFBR1) gene with growth and carcass traits.

Background: Growth and carcass traits are of great economic importance in livestock production. A large number of quantitative trait loci (QTL) have been identified for growth and carcass traits on porcine chromosome one (SSC1). A key positional candidate for this chromosomal region is TGFBR1 (transforming growth factor beta type I receptor). This gene plays a key role in inherited disorders at cardiovascular, craniofacial, neurocognitive, and skeletal development in mammals.

Results: In this study, 27 polymorphic SNPs in the porcine TGFBR1 gene were identified on the University of Illinois Yorkshire × Meishan resource population. Three SNPs (SNP3, SNP43, SNP64) representing major polymorphic patterns of the 27 SNPs in F1 and F0 individuals of the Illinois population were selected for analyses of QTL association and genetic diversity. An association analysis for growth and carcass traits was completed using these three representative SNPs in the Illinois population with 298 F2 individuals and a large commercial population of 1008 animals. The results indicate that the TGFBR1 gene polymorphism (SNP64) is significantly associated (p < 0.05) with growth rates including average daily gains between birth and 56 kg (p = 0.049), between 5.5 and 56 kg (p = 0.024), between 35 and 56 kg (p = 0.021). Significant associations (p < 0.05) were also identified between TGFBR1 gene polymorphisms (SNP3/SNP43) and carcass traits including loin-eye-area (p = 0.022) in the Illinois population, and back-fat thickness (p = 0.0009), lean percentage (p = 0.0023) and muscle color (p = 0.021) in the commercial population. These three SNPs were also used to genotype a diverse panel of 130 animals representing 11 pig breeds. Alleles SNP3_T and SNP43_G were fixed in Pietrain and Sinclair pig breeds. SNP64_G allele was uniquely identified in Chinese Meishan pigs. Strong evidence of association (p < 0.01) between both SNP3 and SNP64 alleles and reproductive traits including gestation length and number of corpora lutea were also observed in the Illinois population.

Conclusion: This study gives the first evidence of association between the porcine TGFBR1 gene and traits of economic importance and provides support for using TGFBR1 markers for pig breeding and selection programs. The genetic diversities in different pig breeds would be helpful to understand the genetic background and migration of the porcine TGFBR1 gene.