Figure 7.

Analysis of X-linked single-copy and multicopy genes. A) Average gene expression of autosomal and X-linked multicopy and single-copy genes. In spermatocytes, there is a significant increase in the average expression level of multicopy genes in the knockout compared to wild type. This increase was not observed for single-copy genes. In round spermatids, there is a small increase in the average expression level of both single-copy and multicopy X-linked genes of Hr6b knockout compared to wildtype, but this is not statistically significant. The autosomes have a similar average expression in all samples. Genes with an expression value <100 in 3 or more samples were excluded. Asterisk indicates significant compared to wild type (p = 0.05). B) The effect of Hr6b knockout on X-linked genes that are repressed in round spermatids (Group A, 278 genes), reactivated in round spermatids (Group B, 33 genes), and genes that are expressed specifically in round spermatids (Group C, 51 genes) as classified by [34]. For group A genes, postmeiotic induction of gene expression is observed only for Hr6b knockout spermatids. For group B and C genes a small increase in the average expression was observed in Hr6b knockout spermatids, compared to wild type spermatids, but this was not statistically significant. In addition, spermatid-specific X-linked genes show premature expression in spermatocytes of Hr6b knockout mice (p = 0.0019)