Comparative genomics between fly, mouse, and cattle identifies genes associated with sire conception rate

Abstract

The decline in reproductive performance in cattle is of major concern to farmers and the dairy industry worldwide. Most fertility studies in cattle have focused on fertility of the cow, whereas the genetics of male fertility have not been thoroughly investigated. The present study hypothesizes that the high conservation of spermatogenesis genes from fly to human implies important roles of these genes in male fertility in cattle. To test this hypothesis, we performed an association analysis between highly conserved spermatogenesis genes and sire conception rate (SCR) in US Holsteins as a measure of bull fertility. Sequencing analysis revealed 24 single nucleotide polymorphisms (SNP) in 9 genes in the bull population using the pooled DNA sequencing approach. Five SNP previously identified in 5 genes from the POU1F1 pathway were also included in this study because they have shown significant associations with female and male fertility traits. Overall, 29 SNP located in 14 candidate genes were tested for association with sire conception rate in a population of 1,988 bulls. Three SNP located in MAP1B and 1 SNP in PPP1R11 showed significant associations with SCR. For the POU1F1 pathway, single gene analysis revealed significant associations of POU1F1 and STAT5A with SCR. Analysis of genotypic interactions between adjacent genes in the pathway revealed significant associations of STAT5A and UTMP genotypic combinations with SCR. The most significant spermatogenesis gene, MAP1B, was found to be associated with fertilization and blastocyst rates. Thus, the association of these genes with bull fertility testifies to the usefulness of the comparative genomics approach in selecting candidate male fertility genes.