In the process of anterior pituitary gland development and maturation, numerous transcription factors were involved in the pituitary organogenesis. To date, the lack of knowledge on POU1F1-PROP1-PITX1-SIX3 pathway genes affecting growth traits was reported in Chinese goat breeds. The objective of this work was to identify genetic variants of the POU1F1, PROP1, PITX1 and SIX3 genes, as well as to evaluate their associations with growth traits in goats. The results showed that one novel and five reported single nucleotide polymorphisms (SNP) were confirmed in above four genes. The novel SNP (NC_019460.2:g.1100T>A) was located in intron 1 of SIX3 gene. Among these loci, DQ826397.1:g.102T>G (SNP1), DQ826397.1:g.279T>C (SNP2) and NC_019460.2:g.1100T>A (SNP6) were associated with growth traits. In details, the SNP1 locus had significant association with hucklebone width (P<0.05) and hucklebone width index (P<0.05) in the Guanzhong dairy goat. The SNP2 locus was associated with body weight (P<0.05), chest circumference (P<0.01), chest width (P<0.05), hucklebone width (P<0.05), cannon circumference (P<0.01) and trunk index (P<0.01) in the Hainan black goat. The SNP6 locus was significantly associated with hucklebone width index (P<0.05) and chest width (P<0.05) in the Guanzhong dairy goat and Hainan black goat, respectively. These findings indicated that goat POU1F1-PROP1-PITX1-SIX3 pathway genes were important genetic factors, which could affect growth traits. Three SNPs detected in this study may be useful for potential marker-assisted selection programs in goat breeding and production.

The growth of skeletal muscle involves complex developmental processes that play an important part in the determinization of pork quality. The investigation of skeletal muscle mRNA or miRNA profiles is especially important for finding molecular approaches to improve meat quality in pig breeding. Therefore, we studied the transcriptome (mRNA and miRNA) profiles of skeletal muscle with RNA-Seq in three developmental stages of pigs: 65-day embryonic (E65), postnatal 0 days (natal) and 10 months (adult). We found 10,035, 9050 and 4841 differentially expressed (DE) genes for natal vs. E65, adult vs. E65 and adult vs. natal, 55, 101 and 85 DE miRNA for natal vs. E65, adult vs. E65 and adult vs. natal, respectively. In addition, the target genes of DE miRNA that was in a negative correlation with the corresponding miRNA in the same comparison group were selected for enrichment analysis. Gene Ontology terms were mainly classified into developmental processes. Pathway analysis revealed enrichment in the Rap1 signaling pathway, citrate cycle and oxidative phosphorylation and carbon. Finally, RT-PCR was employed for validating the level of expression of 11 DE miRNA and 14 DEGs. The transcriptome profiles of skeletal muscle from the different developmental stages of the Bamei pigs were obtained. From these data, hundreds of DE miRNA and mRNA, and the miRNA–mRNA regulatory network can provide valuable insights into further understanding of key molecular mechanisms and improving the meat quality in pig breeding.