Structure and Polymorphism Analysis of Transforming Growth Factor Beta Receptor 1 (TGFBR1) in Pigs

Many quantitative trait loci (QTL) for growth and reproductive traits have been detected on the porcine chromosome region 1qter (SSC1qter), making it one of the most important genomic regions for pig breeding. SSC1q corresponds to human chromosome 9, on which lies transforming growth factor beta receptor 1 (TGFBR1). We cloned the porcine TGFBR1 cDNA and gene (as a candidate for QTL) and analyzed the gene structure and polymorphism. Porcine TGFBR1 consists of 9 exons and 8 introns. Intron 2 is alternatively spliced at the acceptor site, resulting in two kinds of mRNA, with putative open reading frames of 1500 and 1512 bp in length. The shorter one encodes 499 amino acid residues. The amino acid sequence has 96.2 and 97.2% sequence similarity to those of human and bovine TGFBR1, respectively. The sequence similarity between porcine and murine TGFBR1 is 95.6%. We detected three single-nucleotide substitutions in exons 1, 2, and 7. Those in exons 1 and 7 are nonsynonymous substitutions resulting in Pro8Ser and Ile413Val substitutions, respectively.