Selvaggi Maria, Dario Cataldo, Normanno Giovanni, Celano Gaetano V, Dario Marco
Department of Animal Health and Welfare, University of Study of Bari, strada prov. le per Casamassima Km 3-70010 Valenzano, Italy.
J Dairy Res. 2009 Nov;76(4):441-5. doi: 10.1017/S0022029909990070. Epub 2009 Jul 29.
STATs are a group of transcription factors that mediate actions of a variety of peptide hormones and cytokines within target cells (for example, prolactin and growth hormone). Therefore, STAT5A gene is a candidate marker for quantitative traits in farm animals with respect to milk production traits. In this study the STAT5A/AvaI polymorphism was investigated with PCR-RFLP in a sample of 233 Italian Brown cattle. This polymorphism is localized in the coding region of the bovine STAT5A gene. It is a substitution C-->T at position 6853 within exon 7. All three possible genotypes for the C/T polymorphism were identified. The overall frequencies of alleles C and T were 0.83 and 0.17 respectively; the Hardy-Weinberg equilibrium was verified. In order to study the relationship between STAT5A/AvaI polymorphism and milk performance traits, the data for a 305-d milk production that included milk yield, protein and fat yield, fat and protein percentage were used. Significant differences between the two genotypes were found in yields of milk, fat and protein and protein percentage (P<0.01). CC cows produced more milk than CT (5418.68 v. 5149.54 kg). Protein content was higher in milk from CC compared with CT genotypes (3.40 v. 3.21%). No significant difference was found in fat content. Owing to the low number of TT cows in the studied population, this genotype was not included in the statistical analysis; in fact the number of TT cows was not enough to provide an accurate statistical analysis. Although more studies are needed to better clarify the role of this SNP on production traits, STAT5A/AvaI polymorphism appears to be a promising indirect marker to improve milk production traits in cattle.
信号转导子和转录激活子（STATs）是一组转录因子，可介导多种肽类激素和细胞因子在靶细胞内的作用（例如催乳素和生长激素）。因此，就产奶性状而言，STAT5A基因是家畜数量性状的候选标记。在本研究中，采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）技术对233头意大利褐牛样本中的STAT5A/AvaI多态性进行了研究。这种多态性位于牛STAT5A基因的编码区。它是外显子7内第6853位的C→T替换。已鉴定出C/T多态性的所有三种可能基因型。等位基因C和T的总体频率分别为0.83和0.17；验证了哈迪-温伯格平衡。为了研究STAT5A/AvaI多态性与产奶性能性状之间的关系，使用了305天产奶量的数据，包括产奶量、蛋白质和脂肪产量、脂肪和蛋白质百分比。在产奶量、脂肪和蛋白质产量以及蛋白质百分比方面，两种基因型之间存在显著差异（P<0.01）。CC基因型奶牛的产奶量高于CT基因型奶牛（5418.68对5149.54千克）。CC基因型牛奶中的蛋白质含量高于CT基因型（3.40对3.21%）。脂肪含量未发现显著差异。由于研究群体中TT基因型奶牛数量较少，该基因型未纳入统计分析；实际上，TT基因型奶牛的数量不足以提供准确的统计分析。尽管需要更多研究来更好地阐明该单核苷酸多态性对生产性状的作用，但STAT5A/AvaI多态性似乎是改善奶牛产奶性状的一个有前景的间接标记。
