中文摘要：

信号转导与转录激活因子家族（STATs）是一组介导靶细胞内多种肽类激素和细胞因子活性的转录因子.因此,STAT5A基因近年被确定为一个与普通奶牛泌乳性状相关的候选基因,但目前在水牛中该基因的研究报道还比较少.本研究采用PCR产物直接测序技术对60头河流型水牛和300头沼泽型水牛样品的STAT5A基因外显子7,8,9,13和16序列及内含子8序列、内含子16部分序列进行了群体变异检测,并对检测结果进行了群体遗传和比较基因组学分析.在水牛STAT5A基因中共检测到12个SNP位点,其中在外显子中检测到4个SNP位点,内含子中检测到8个SNP位点.在外显子8和外显子13中各检测到2个SNP位点,在外显子8中为c.924C＞T和c.975C ＞T替换,在外显子13中为c.1485A＞G和c.1551C ＞T替换.它们均为同义替换,只存在于河流型水牛中.在内含子8中检测到7个SNP位点,在内含子16中检测到1个SNP位点.在内含子中检测到的SNP位点全部存在于河流型水牛中,在沼泽型水牛中只存在其中的2个SNP位点（c.989＋ 144G＞T,c.989＋ 177A＞ G）.本文结果揭示河流型与沼泽型水牛STAT5A基因SNP位点群体遗传组成不同,在河流型水牛中检测到的SNP位点大多在沼泽型水牛中已纯合.比较基因组学分析显示,水牛与普通牛、牦牛和绵羊的STAT5A基因序列差异较大,水牛具有不同的SNP位点分布模式,但水牛与普通牛和牦牛在氨基酸序列水平上差异较小.

英文摘要：

Signal transducers and activators of transcription （STATs） are a group of transcription factors that mediate actions of a variety of peptide hormones and cytokines within target cells. Therefore, STAT5A gene is identified as a candidate gene associated with milk production traits in dairy cattle, butat present, there are few research reports on buffalo STATSA gene. In this study, the polymorphisms in exon 7, 8, 9, 13 and 16, and in intron 8 and a part of intron 16 of STAT5A gene of 60 river buffalo and 300 swamp buffalo were detected by PCR and direct DNA sequencing. The data obtained were dealt with the methods of population genetics and comparative genomics further. A total of 12 SNPs were identified in buffalo STATSA gene, 4 exonic and 8 intronic. Two exonic synonymous substitutions were identified only in the exon 8 and 13 of river buffalo, respectively. They were c. 924C 〉 T and c. 975C 〉 T in the exon 8, c. 1485A 〉 G and c. 1551C 〉 T in the exon 13. Seven SNPs were identified in intron 8 and 1 SNP in intron 16, of which all were found in the river buffalo and only 2 SNPs （c. 989 ＋144G 〉T, c. 989 ＋ 177A 〉G） were found in the swamp buffalo. The results revealed that river and swamp buffalo possessed different population genetic compositions and most of the SNPs identified in river buffalo had been homozygous in swamp buffalo. Comparative genomics analysis showed there were large sequence differences of STAT5A gene between buffalo and cattle, yaks and sheep, and compare to other bovine species buffalo had different SNP distribution patterns, but there were small differences in the amino acid sequences of STATSA between buffalo and cattle and yak.