Single-nucleotide polymorphism analysis of GH, GHR,and IGF-1 genes in minipigs

Tibetan (TB) and Bama (BM) miniature pigs are two popular pig breeds that are used asexperimental animals in China due to their small body size. Here, we analyzedsingle-nucleotide polymorphisms (SNPs) in gene fragments that are closely related togrowth traits [growth hormone (GH), growth hormone receptor(GHR), and insulin-like growth factor(IGF)-1)] in these pig breeds and a large white(LW) control pig breed. On the basis of the analysis of 100 BMs, 108 TBs, and 50 LWs,the polymorphic distribution levels of GH, GHR, andIGF-1 were significantly different among these three pig breeds.According to correlation analyses between SNPs and five growth traits - body weight(BW), body length (BL), withers height (WH), chest circumference (CC), and abdomencircumference (AC) - three SNP loci in BMs and four SNP loci in TBs significantlyaffected growth traits. Three SNP sites in BMs and four SNP sites in TBssignificantly affected growth traits. SNPs located in the GH genefragment significantly affected BL and CC at locus 12 and BL at locus 45 in BMs, andalso BW, WH, CC, and AC at locus 45 and WH and CC at locus 93 in TBs. One SNP atlocus 85 in the BM GHR gene fragment significantly affected allgrowth traits. All indices were significantly reduced with a mixture of alleles atlocus 85. These results provide more information regarding the genetic background ofthese minipig species and indicate useful selection markers for pig breedingprograms.