Ancestral Chromatin Configuration Constrains Chromatin Evolution on Differentiating Sex Chromosomes in Drosophila
Fig 5
Dosage compensation in male D. busckii.
A. Immunostaining of male and female D. busckii polytene chromosomes with MSL-2 antibody. The neo-X / X chromosome is marked with an arrow, and the male X shows binding of MSL-2 protein. B. Comparison of normalized log2 enrichment level of H4K16ac across genes on different chromosomes. Enrichment level of H4K16ac on X-linked genes (red) is significantly higher (Wilcoxon test, P<0.001) than on any other chromosomes, while neo-sex linked genes show a significantly lower enrichment level than autosomes (green), and there is no significant difference between the neo-X (orange) and neo-Y (blue) alleles. C. Enrichment level of H4K16ac is strongly correlated between orthologous genes of D. melanogaster and D. busckii. Genes are color-coded according to chromosomal location. D-E. Metagene profiles of H4K16ac over active (D.) and silent (E.) genes. For neo-sex genes, we defined the expression status by the expression level of neo-X alleles. Note that H4K16ac is significantly more enriched at active X-linked genes, and shows a characteristic 3’ binding bias.