growth hormone; single-nucleotide polymorphisms; linkage disequilibrium analysis; body size.
Growth hormone (GH) has been considered as a candidate gene for growth and body size in pigs. In this study, polymorphisms of the GH1 gene were evaluated for associations with body size traits in 190 pig individuals. Seventeen single-nucleotide polymorphisms (SNPs) were identified in GH1 gene of the large pig breeds and miniature pig breeds using direct sequencing and genotyped by allele-specific PCR approach. Notably, six (𝑔.237A>G, 𝑔.283T>C, 𝑔.309A>G, 𝑔.318A>G, 𝑔.540A>G and 𝑔.544A>G) of them were significantly associated with body size, of which three loci (𝑔.283T>C, 𝑔.309A>G, 𝑔.318A>G) located in the signal-peptide coding region of GH1 gene compose a CGG haplotype for large pigs and TAA haplotype for miniature pigs (𝑃 < 0.001), two loci (𝑔.540A>G and 𝑔.544A>G) located in the second intron of GH1 gene compose a GG haplotype for large pigs and AA haplotype for miniature pigs (P < 0.001). Our results demonstrate that these SNPs in GH1 gene are associated with the body size of pigs providing genetic basis for pig breeding with the improved economic benefits.