Differentially expressed genes in X- and Y-spermatozoa of Bos indicus bulls

The X- and Y-chromosome bearing spermatozoa (X- and Y-sperm) differ in their DNA content, and this difference may be responsible for the differential expression of certain genes. The present study aimed to validate the differential gene expression (DGE) in X- and Y-sperm of Bos indicus bulls to investigate sex-specific differences. Based on the transcriptome dataset, 21 genes were validated by qPCR for their uniqueness/relative expression. Eleven genes in Y-sperm (TA1CL, CPA1, RAB6A, RAB27A, SPATA5L1, SPATS1, TEKT3, TUBB1, TG2C, VDAC1, and SPATA6L) and ten genes in X-sperm (8G2, ADD3, BD, EXOSC1, H2A, DNAJC9, ITPR1P, LEPROTL1, LRRTM3, and SPADH2) are associated with spermatogenesis, motility, capacitation, and fertilization. The qPCR analysis revealed upregulation of nine genes in Y-sperm and eight genes in X-sperm (p < 0.01, p < 0.05), in accordance with the transcriptome dataset. The genes upregulated in Y-sperm are associated with sperm motility and those upregulated in X-sperm with survivability under stress conditions.