Polymorphisms of the bone morphogenetic protein 7 gene (BMP7) and association analysis with sow productive traits

Bone morphological protein 7 (BMP7) has been proposed to be an osteoinductive protein. Recent data have shown that BMP7 also plays a crucial role in the growth and development, and physiological function of reproductive system. To date, studies have shown an association between the BMP gene family and reproduction in many populations, but few studies have completely described this association in sow. In the present study, three sow breeds were screened out to investigate the genetic effects of the BMP7 gene. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing, three single nucleotide polymorphisms (SNPs) (g.35161T>C, g.35175T>C and g.35216C>T) were identified in intron 2 of the BMP7 gene. Associations between the three SNPs and the number of piglet born alive (NBA), litter weight at birth (LBW), total number of piglet born (TNB) and litter weight at 21 days were analyzed using association analysis. Among the three SNPs, g.35161T>C was significantly associated with NBA and LBW (p<0.05), and the litter weight at 21 days (p<0.01). These results suggest that g.35161T>C is a potential candidate gene locus for litter size traits and the BMP7 gene might be associated with the quantitative trait locus (QTL) controlling the litter size. These data will provide a background for more extensive characterization of the BMP7 gene.