Effects of genetic variations within goat gene on growth traits and mRNA expression.

Paired-like homeodomain 2 (), a key gene in hypothalamic-pituitary-adrena axis, influences animal growth and development. The objective of this study was to identify the association of the functional genetic variations within goat gene with growth traits and mRNA expression levels. According to the reported single nucleotide polymorphisms (SNPs) information in Guanzhong dairy goat (GZDG), we identified genotypes of the known SNPs in Hainan black goat (HNBG). Association analysis uncovered that the SNPs of AC_000163: g.18117T > C, g.18161C > G and g.18353T > C loci were significantly associated with several growth traits (e.g., body height and body length) in HNBG and GZDG breeds. According to the quantitative real-time PCR assay, and ribosomal protein L19 () were the most stable expressed housekeeping genes in heart and skeletal muscle, respectively; meanwhile, glyceraldehyde-3-phosphate dehydrogenase () was the most stable expressed housekeeping gene in the other tissues. Based on the best housekeeping gene of varied tissues, we found the different genotypes of above loci were significantly associated with mRNA expression in heart, muscle and small intestine. Briefly, the genetic variants of goat associating with mRNA expression affected growth traits significantly, which would benefit for goat breeding in the future.