Myostatin (MSTN) gene negatively controls skeletal muscle development and growth, variations of which play an important role in the regulation of skeletal muscle growth in mammals.  However, study on genetic polymorphism of MSTN gene in donkey is limited.  In this study, we screened the single nucleotide polymorphsims (SNPs) of MSTN gene in 13 Chinese donkey breeds.  Four novel SNPs (g.229T>C, g.872A>G, g.2014G>A, and g.2395C>G) were detected and genotyped by sequencing and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods.  Six haplotypes (H1–H6) were analyzed, which indicated abundant haplotype diversities in Chinese donkeys.  The haplotype H1 was the most dominant and ancient in all breeds.  Xinjiang donkey displayed the highest haplotype diversity.  The Neighbour-Joining (NJ) tree of MSTN gene among different species was constructed.  The clustering result of nine species was consistent with the fact of species differentiation.  Our results will provide a reliable theoretical basis for the preservation, exploration and utilization of Chinese donkey genetic resources.

Paired-like homeodomain transcription factor 1 (PITX1) plays an important role in pituitary development by indirectly regulating the expression of the GH and PRL genes, and therefore PITX1 gene is regarded as a potential candidate gene for building the relationship between the gene polymorphism and milk traits. The aim of this study was to explore the novel genetic variant in PITX1 gene and its effect on milk performance in dairy goats. Herein, a novel genetic variation (NW_00314033: g.201G>A or IVS1+41G>A) located at nt41 position of the first intron of the goat PITX1 gene was reported at the P1 locus, which can be genotyped by the Msp I PCR-RFLP. In the Msp I PCR-RFLP analyis, the GG variant was a major genotype, and the A variant was a minor allele in Guanzhong dairy goats which was at Hardy-Weinberg disequilibrium (chi-square c2=140, P<0.01). The establishment of associations between different genotypes and milk performance was performed in the analyzed population. A total of three significant associations of the polymorphism with average milk fat content (%) (P=0.045), morning milk fat content (%) (P=0.049), and afternoon milk fat content (%) (P=0.050), were found, respectively. A significant relationship between the polymorphism and average total solid content (P=0.029) was also detected. This novel single nucleotide polymorphism (SNP) extended the spectrum of genetic variation of the goat PITX1 gene, and its significant association with milk performance would benefit from the application of DNA markers related to improving milk performance through marker-assisted selection (MAS) in dairy goats.

Visfatin, like insulin, induces phosphorylation of signal transduction proteins that operatate downstream of the insulin receptor. The present study is focused on detecting deletion of visfatin gene and analyzing its effect on growth traits in six Chinese cattle breeds (Nangyang, Luxi, Qinchuan, Jiaxian Red, Grassland Red, and Chinese Holstein) using DNA sequencing, PCR-SSCP and PCR-RFLP methods. For the first time, a 6-bp deletion of visfatin was described and two alleles were revealed: W and D. The χ2-test analysis demonstrated that all breeds were in agreement with Hardy-Weinberg equilibrium (P>0.05). The associations of the novel 6-bp deletion of visfatin gene with growth traits of Nanyang cattle at 6-, 12-, 18-, and 24-mon-old were analyzed. Birth weight, 12- and 24-mon-old cattle with genotype WW had greater birth weight and average daily gain than genotype WD (P<0.01 or P<0.05). These results suggest that the deletion may influence the birth weight and bodyweight in 12 mon-old cattle.

Orexin is an important neuropeptide that influences livestock’s appetite and food intake and is closely related withlivestock’s growth and development. The variations in the orexin gene 5´ regulatory region might have an influence onthe gene expression. Based on the hypothesis, five overlapped fragments including 1 794 bp of orexin gene 5´ regulatoryregion were investigated for single nucleotide polymorphisms (SNPs) by PCR-SSCP and DNA sequencing in threeindigenous cattle populations. A total of five SSCP patterns observed revealed ten SNPs in the region. Two SSCP patternsgenotypes (A and B) were exhibited in O-2 fragment and three (A, B and C) were found in O-5 fragment. O-2 contained fourSNPs, viz., -583 T>C, -479 C>T, -474 A>T, and -451 A>G. In another lous O-5, six SNPs were identified (-1 610 C>G,-1 585 G>A, -1 550 T>C, -1 548 A>C, -1 438 C>T, and -1 431 C>A). Seven SNPs were found in transcription factor bindingsites and four out of them existed in the core sequences. The SNPs at -479, -474 and -451 did not change the putativerecognition core sequences of their factors. But the mutation at -583 changed the binding sequence of EVI1 into NFA andcreated one new binding site for ZFHX simultaneously. In three populations, the frequencies of A, B and C genotypesof O-2 were 0.2367, 0.4842 and 0.2791, respectively. And the A pattern of O-5 was preponderant (0.7549) and the other Bpattern was not (0.2451). But the frequencies of different SSCP variants varied across three cattle populations. Bgenotype in O-2 had significant associations to body weight (BW) and daily weight gain (DWG) in Nanyang cattle 6- and12-mon aged and might serve as one potential candidate genetic marker for growth and development.