牛科物种FSHβ基因外显子1和外显子2遗传特征分析

Genetic Characteristics on Exon 1 and Exon 2 of FSHβ Gene in the Species of Family Bovidae

促卵泡素(follicle-stimulating hormone,FSH)对刺激动物卵泡发育和促进精子生成具有重要作用,但有关牛科物种FSH基因的群体遗传特征还不十分清楚。本文针对FSHβ基因外显子1和外显子2,采用PCR-SS-CP结合PCR产物直接测序技术对353头水牛(来自11个水牛群体)、30头牦牛和30头大额牛样品进行了群体变异检测,并结合NCBI数据库中已发表的普通牛、山羊和绵羊等物种同源序列进行了群体遗传和生物信息学分析。在FSHβ基因外显子1中,水牛中发现1个核苷酸替换和1个缺失,即c.-49A>G和c.-31delG;其中,SNP-49在河流型和沼泽型水牛中均存在,等位基因c.-49A为优势等位基因,而c.-31delG只存在于沼泽型水牛中,且为杂合状态,基因频率为0.077。在牦牛外显子1中检测到c.-37G>A和c.-12T>C替换,且为连锁遗传的,而在大额牛外显子1中未检测到SNP位点。在FSHβ基因外显子2中,水牛中发现c.132G>A替换,该位点在河流型和沼泽型水牛均存在,但等位基因频率在两类水牛间不一致。在牦牛外显子2中检测到c.9C>T和c.21C>T替换,该替换也存在于普通牛中;大额牛外显子2为单态,未见SNP位点。生物信息学分析显示,在一些牛科物种FSHβ基因外显子2中发现的SNP位点均为同义替换,揭示了其序列的高度保守性。在牛科物种中,山羊和绵羊FSHβ基因第36位密码子编码氨基酸与其他物种不同,可作为区分它们的遗传标记。

Follicle-stimulating hormone （FSH） plays an essential role in mammalian follicular devel-opment and spermatogenesis, but the population genetic characteristics about FSH gene in bovine spe- cies is unclear. In this study, the polymorphisms in the exon 1 and exon 2 of FSHfl gene were assayed by using the methods of PCR-SSCP with DNA sequencing in 353 water buffalo which belong to 11 dif- ferent populations, 30 yaks and 30 gayals. And population genetics and bioinformatics analysis was conducted on the data obtained in this study and retr/eved from NCBI database which included homolo- gous DNA sequences in some species such as cattle, goat and sheep. For the exon 1 of FSHfl gene, one substitution and one deletion were identified in the water buffalo, namely c. -49A 〉 G and c. - 31delG. The former was simultaneously present in river and swamp buffalo which e. -d9A was major allele, whereas the latter was only found in swamp buffalo which exist in heterozygosis and its gene fre- quency was 0. 077. Substitution c. - 37G 〉 A and c. - 12T 〉 C were identified in the exon 1 of FSHj8 gene in yak, which were linked together, but no SNP was found in the exonl of FSHfl gene in gayal. For the exon 2 of FSHfl gene, substitution c. 132G 〉 A was detected in river and swamp buffalo, but the gene frequencies at this locus are different in two kind of buffalo. Substitution c. 9C 〉 T and c. 21C 〉 T were found in the exon 2 of FSHβ gene of yak, which also existed in cattle. The exon 2 of FSHfl gene in gayal was still monomorphic. The results by bioinformatics analysis revealed the SNPs found in the exon 2 of FSHβ gene of some bovine species were all synonymous, which indicated that it was highly conservative in phylogenesis. In the species of family Bovidae, the amino acid encoded by codon 36 of FSHβ gene in goat and sheep was different with other bovine species, which can be used as the genetic marker to distinguish them from other bovine species.