Cao Haiyue, Dong Xinyang, Mao Haiguang, Xu Ningying, Yin Zhaozheng
Animal Science College, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
Animals (Basel). 2019 Nov 20;9(12):1001. doi: 10.3390/ani9121001.
PITX2 is expressed in and plays an important role in myocytes of mice, and it has effects on late myogenic differentiation in chickens. However, the expression profile and polymorphisms of PITX2 remain unclear in chickens. Therefore, the aim of the present study was to detect its expression and investigate single nucleotide polymorphisms (SNPs) within its exons and then to evaluate whether these polymorphisms affect body size as well as carcass traits in chickens. The expression analysis showed that the expression level of chicken PITX2 mRNA in the leg muscle and hypophysis was significantly higher (p < 0.01) than those in other tissues. The results of polymorphisms analysis identified two SNPs (i.e., g.9830C > T and g.10073C > T) in exon 1 and 10 SNPs (i.e., g.12713C > T, g.12755C > T, g.12938G > A, g. 3164C > T, g.13019G > A, g.13079G > A, g.13285G > A, g.13335G > A, g.13726A > G and g.13856C > T) in exon 3, including four novel SNPs (i.e., g.9830C > T, g.12713C > T, g.12938G > A and g.13856C > T). In the loci of g.10073C > T and g.12713C > T, chickens with the CT genotype had the highest (p < 0.05 or p < 0.01) breast depth and breast angle, respectively. For the locus of g.13335G > A, chickens with the GG genotype had the highest (p < 0.05 or p < 0.01) breast angle and shank circumference. For the locus of g.13726A > G, chickens with the GG genotype had the highest breast width, fossil keel bone length and shank circumference. The locus of g.12713A > G had significant effects on the PITX2 mRNA expression level in leg muscle. The H1H7 diplotype showed the highest shank circumference, and the H2H8 diplotype showed the highest breast muscle rate. The present research suggested that polymorphisms of the exons of the PITX2 gene were significantly associated with the body size and carcass traits of Wuliang Mountain Black-bone chickens and the PITX2 gene could be a potential candidate gene for molecular marker-aided selection in Wuliang Mountain Black-bone chickens and other chicken breeds.
PITX2在小鼠的心肌细胞中表达并发挥重要作用，且对鸡的晚期成肌分化有影响。然而，PITX2在鸡中的表达谱和多态性仍不清楚。因此，本研究的目的是检测其表达，并研究其外显子内的单核苷酸多态性（SNP），然后评估这些多态性是否影响鸡的体型和胴体性状。表达分析表明，鸡PITX2 mRNA在腿部肌肉和垂体中的表达水平显著高于其他组织（p < 0.01）。多态性分析结果在第1外显子中鉴定出2个SNP（即g.9830C>T和g.10073C>T），在第3外显子中鉴定出10个SNP（即g.12713C>T、g.12755C>T、g.12938G>A、g.3164C>T、g.13019G>A、g.13079G>A、g.13285G>A、g.13335G>A、g.13726A>G和g.13856C>T），包括4个新的SNP（即g.9830C>T、g.12713C>T、g.12938G>A和g.13856C>T）。在g.10073C>T和g.12713C>T位点，CT基因型的鸡分别具有最高的胸深和胸角（p < 0.05或p < 0.01）。对于g.13335G>A位点，GG基因型的鸡具有最高的胸角和胫围（p < 0.05或p < 0.01）。对于g.13726A>G位点，GG基因型的鸡具有最高的胸宽、胸骨化石长度和胫围。g.12713A>G位点对腿部肌肉中PITX2 mRNA表达水平有显著影响。H1H7双倍型显示最高的胫围，H2H8双倍型显示最高的胸肌率。本研究表明，PITX2基因外显子的多态性与无量山乌骨鸡的体型和胴体性状显著相关，PITX2基因可能是无量山乌骨鸡和其他鸡品种分子标记辅助选择的潜在候选基因。
