A tremendous expansion of TSPY copy number in crossbred bulls (Bos taurus x Bos grunniens)

作者：Zhang, G. W.; Guan, J. Q.; Luo, Z. G.; Zhang, W. X.; Wang, L.; Luo, X. L.; Zuo, F. Y.^*

来源：Journal of Animal Science, 2016, 94(4): 1398-1407.

DOI：10.2527/jas.2015-9983

• male infertility
• copy number variations
• TSPY gene
• male-specific regions of the mammalian Y chromosome
• yak

Crossbreeding between cattle (Bos taurus) and yak (Bos grunniens) exhibits significant hybrid advantages in milk yield and meat production. By contrast, cattle-yak F-1 hybrid bulls are sterile. Copy number variations (CNV) of multicopy gene families in male-specific regions of the mammalian Y chromosome (MSY) affect human and animal fertility. The present study investigated CNV of TSPY (testis-specific protein, Y-encoded), HSFY (heat-shock transcription factor, Y-linked), ZNF280BY (zinc finger protein 280B, Y-linked), and PRAMEY (preferentially expressed antigen in melanoma, Y-linked) in 5 yak breed bulls (n = 63), cattle-yak F-1 (n = 22) and F-2 (n = 2) hybrid bulls, and Chinese Yellow (CY) cattle bulls (n = 10) by quantitative real-time PCR. TSPY showed restricted amplification in yak bulls in that the average geometric mean copy number (CN) was estimated to be 4 copies. The most compelling finding is that there is a tremendous expansion of TSPY CN in F-1 hybrids (385 copies; 95% confidence interval [CI] = 351-421) and F-2 hybrids (356 copies) compared with the male parent breed CY cattle (142 copies; 95% CI = 95-211). Copy numbers of HSFY and ZNF280BY were also extensively expanded on the Y chromosome in yak and CY cattle bulls. The geometric mean CN of HSFY and ZNF280BY were estimated to be 123 (95% CI = 114-132) and 250 copies (95% CI = 233-268) in yak bulls and 71 (95% CI = 61-82) and 133 (95% CI = 107-164) copies in CY cattle, respectively. Yak and CY cattle have 2 copies of the PRAMEY gene on the Y chromosome. Similarly to TSPY gene, the F-1 and F-2 hybrid bulls have higher CN of HSFY, ZNF280BY, and PRAMEY than CY cattle (P < 0.01). These results indicated that the MSY of yak and cattle-yak crossbred hybrids was fundamentally different from cattle MSY in the context of genomic organization. Based on the model of cattle-yak F-1 and F-2 hybrid bull sterility, the CNV of TSPY may serve as a potential risk factor for crossbred bull (B. taurus x B. grunniens) infertility. To our knowledge, this is the first study to examine differences in multicopy genes in MSY between yak and cattle-yak bulls.

• 出版日期2016-4
• 单位西南大学; 四川省草原科学研究院