CNVs of Two Y-Linked Genes, HSFY and ZNF280BY, in Cattle and Their Association with Male Fertility in Holstein Sires

Recent transcriptomic analysis of the bovine Y chromosome revealed six multi-copy protein coding gene families, including TSPY, HSFY and ZNF280BY, on the male-specific region (MSY). The copy number variations (CNVs) of TSPY have been studied and found to be associated with male fertility in cattle. In this study, we investigated the CNVs of the bovine HSFY and ZNF280BY among 460 bulls from 15 breeds using a quantitative PCR approach. We observed significant variations (P < 0.05) in copy number (CN) for both gene families within and between cattle breeds. The median CN (MCN) of HSFY among individuals tested was 197 (ranging from 21 to 308), while it was 236 (28 to 380) for ZNF280BY. The MCN of HSFY (202) in the Bos taurus (BTA) lineage was significantly higher than that (178) in the Bos indicus (BIN) lineage. In contrast, the MCN of ZNF280BY (231) in the BTA lineage was significantly lower than that (284) in the BIN lineage. Our data indicated that the amplification of the HSFY and ZNF280BY gene families during evolution may be related to the sequence rearrangements between BTAY and BINY. Association analysis in 257 Holstein bulls revealed that the CNVs of both HSFY and ZNF280BY were correlated negatively with testis size, positively with sire conception rate, but not significantly correlated with semen quality index, non-return rate and relative breeding efficiency, suggesting that the CNVs of HSFY and ZNF280BY may serve as valuable makers for male fertility selection at an early age in cattle.