Association of SNPs Located in Different Candidate Genes with Growth Traits in Two Japanese Quail Lines

This study investigated the association of polymorphisms in four genes with growth traits in two Japanese quail lines: a high-growth-rate selected line (HGR) and a control line (CL). It utilized 21 generations of divergent selection to identify potential selection signatures, comparing allele frequency shifts between the high-growth and unselected base populations. Growth Hormone (GH), Prolactin (PRL), Bone Morphogenetic Protein Receptor Type-1B (BMPR-1B), and Vasoactive Intestinal Peptide Receptor 1 (VIPR-1) genes were genotyped using PCR-RFLP. While the PRL gene was monomorphic, the GH, BMPR-1B, and VIPR-1 loci were polymorphic. Association analysis demonstrated that these variants significantly influenced body weight. In the HGR line, the homozygous genotypes (BB) of GH and BMPR-1B were significantly correlated with increased body weight at various ages. The AA genotype of VIPR-1 correlated with growth, while the BB genotype reduced body weight. An in silico analysis suggested that GH and VIPR-1 variants were functionally disadvantageous. The BMPR-1B variant was tolerated, indicating its potential as a genetic marker. Significant additive effects were estimated for the associated SNPs, thereby highlighting their heritable potential. These findings suggest that GH, BMPR-1B, and VIPR-1 polymorphisms are valuable for marker-assisted selection to improve growth performance within Japanese quail breeding programs.