Figure 7.
Not only protein-coding sequences but also gene regulatory mechanisms were preserved during the evolution of sex chromosomes from ordinary autosomes. The auto- and cross-regulation of DDX3X and DDX3Y reported here likely originated from the auto-regulation of ancestral (autosomal) DDX3X. Together with published studies of two other X–Y gene pairs—EIF1AX-EIF1AY and ZFX-ZFY (Godfrey et al. 2020; San Roman et al. 2024)—our findings suggest that an array of gene-specific regulatory schemes operative on the ancestral autosomes persist today on human Chr X and Chr Y.
