为了揭示牛科物种INHA基因的遗传特征, 该文采用PCR产物直接测序法对水牛、大额牛和牦牛INHA基因外显子1及其侧翼序列进行多态性检测, 并结合已发表的包括牛科物种在内的一些哺乳动物数据进行了比较分析。结果表明, 在水牛INHA基因外显子1中存在c.73C>A替换, 为同义替换, 河流型和沼泽型水牛编码产物一致; 在大额牛的INHA基因外显子1中发现c.62 C>T、c.187 G>A替换, 分别引起INHA中氨基酸发生p. P21L、p. V63M改变, 两者均为相同性质氨基酸的替换; 在牦牛中发现c.62 C>T、c.129A>G替换, 前者也引起编码氨基酸发生p. P21L替换, 后者为同义替换。在INHA基因5'侧翼区所测出的序列中, 水牛、大额牛和牦牛等物种内均未发现SNP位点, 但在种间发现存在c. -6T>G的替换, 大额牛、牦牛和普通牛均为c. -6G, 而水牛为c. -6T。在INHA基因内含子中, 水牛的第31~36位核苷酸处发现有6个碱基的缺失, 即c. 262+31_262+36delTCTGAC; 该位点在河流型水牛中野生型(+/+)占主体, 而在沼泽型水牛中则缺失型(-/-)占主体。在大额牛、牦牛和普通牛等其它牛科物种的内含子中均未发现该缺失, 但与水牛相比, 大额牛、牦牛和普通牛内含子中发现缺失c. 262+78_262+79delTG。序列比对显示,INHA基因外显子1序列中c. 43A和c. 67G为水牛中所特有, 而c. 173A和c. 255G 为大额牛、牦牛和普通牛所共有, c. 24C、c. 47G、c. 174T和c. 206T为山羊所特有。大额牛、牦牛和普通牛间INHA基因外显子1序列差异较小, 而山羊和水牛与它们间的差异相对较大。
To elucidate the genetic characteristics of the bovine Inhibin α subunit (INHA) gene, the polymorphisms in exon 1 of INHA and its bilateral sequences were assayed using PCR with direct sequencing in buffalo, gayal and yak. A comparative analysis was conducted by pooled the results in this study with the published data of INHA on some mammals including some bovine species together. A synonymous substitution c.73C>A was identified in exon 1 of INHA for buffalo, which results in identical encoding product in river and swamp buffalo. In gayal, two non-synonymous but same property substitutions in exon 1 of INHA, viz. c.62 C>T and c.187 G>A, were detected, which lead to p. P21L, p. V63M changes in INHA, respectively. In yak, nucleotide substitution c.62C>T, c.129A>G were found in exon 1 of INHA, the former still causes p. P21L substitution and the latter is synonymous. For the sequence of the 5'-flanking region of INHA examined, no SNPs were found within the species, but a substitution, c. -6T>G, was found. The nucleotide in this site in gayal, yak and cattle was c. -6G, whereas in buffalo it was c. -6T. Meanwhile, a 6-bp deletion, namely c. 262+31_262+36delTCTGAC, was found in the intron of buffalo INHA gene. For this deletion, wild types (+/+) account for main part in river buffalo while mutant types (-/-) are predominant in swamp buffalo. This deletion was not found in gayal, yak and cattle, though these all have another deletion in the intron of INHA, c. 262+78_262+79delTG. The results of sequence alignment showed that the substitutions c. 43A and c. 67G in exon 1 of INHA are specific to buffalo, whereas the substitutions c. 173A and c. 255G are exclusive to gayal, yak and cattle, and c. 24C, c. 47G, c. 174T and c. 206T are specific to goat. Furthermore, there are few differences among gayal, yak and cattle, but there relatively great differences between buffalo, goat and other bovine species regarding the sequences of INHA exon 1.