Fig. 1.

X chromosome gene expression is disrupted in sterile hybrids at every stage of spermatogenesis. (A) Timeline of spermatogenesis highlighting FACS-enriched cell populations, which span major transitions in gene expression. The sex chromosomes are transcriptionally silenced in early prophase (MSCI) and are repressed during postmeiotic development (PSCR). (B) Cell-specific differential expression (DE) between sterile^MxD hybrids and all fertile males across spermatogenesis. Gray lines are the difference in normalized FPKM for DE genes, plotted along each chromosome (top is the centromere). At every cell stage the X chromosome was enriched for DE genes and enriched for genes overexpressed in sterile^MxD males. All enrichment tests are based on FDR corrected chromosome-wise hypergeometric tests. (C) The proportion of DE genes for the autosomes and the X chromosome. Significant differences are based on FDR corrected Pearson’s chi-squared test. FPKM values are normalized so that the sum of squares equals 1.