中文摘要：

【目的】克隆黄牛、牦牛和犏牛Sycp2基因序列,了解牛Sycp2基因序列特征和组织表达特征,分析睾丸组织中Sycp2基因的表达水平。【方法】采用电子克隆和克隆测序技术获得黄牛、牦牛和犏牛Sycp2基因序列,利用生物信息学方法分析其序列特征;采用RT-PCR分析牛Sycp2基因的组织表达特征;采用real-time PCR技术检测黄牛、牦牛和犏牛睾丸组织Sycp2基因的表达水平。【结果】①黄牛、牦牛和犏牛Sycp2基因编码区序列全长均为4 365 bp,命名为b-Sycp2,编码蛋白含有1 454个氨基酸残基,并包含卷曲螺旋结构域等典型结构域;②b-Sycp2基因在睾丸组织中特异表达,黄牛和牦牛睾丸组织中b-Sycp2基因的表达水平显著高于犏牛（P〈0.05）。【结论】成功克隆了b-Sycp2基因,b-Sycp2基因为睾丸组织的特异表达基因,且黄牛和牦牛睾丸组织b-Sycp2基因表达水平显著高于犏牛。

英文摘要：

[Objective] The study was aimed to clone the Sycp2 gene sequence of cattle, yak and cattle-yak, investigate the gcne structures and its tissue-expression patterns and testicular expression levels in cattle, yak and cattle-yak. [Method] In silico cloning and clone sequencing were applied to acquire the coding region sequences of Sycp2 gene of cattle, yak and yak-cattle, and molecular characterization were analyzed by bioinformatics software. RT-PCR was applied to analyze the tissue-expression patterns, and real-time PCR was employed to examine the expression levels in cattle, yak and cattle-yak testis. [Result] The full length of the coding region sequences of the Sycp2 gene was 4 365 bp, named b-Sycp2. The b-Sycp2 gene in cattle, yak and cattle-yak encoded 1 454 amino acid residues which included some typical domains such as coiled-coil domain. RT-PCR analysis showed that b-Sycp2 gene was expressed only in the testis. Real-time PCR analysis revealed that the mRNA expression level of b-Sycp2 gene in the testis of cattle and yak was remarkably higher than that of in cattle-yak （P〈0.05）. [Conclusion] The b-Sycp2 gene was cloned successfully, and it expressed only in testis, b-Sycp2 mRNA expression level of cattle and yak represented a dramatic higher than that of cattle-yak.