Fig. 6: Toxic Y chromosome and adaptive Y degeneration.
From: Epigenetic conflict on a degenerating Y chromosome increases mutational burden in Drosophila males
Epigenetic conflicts between host-specific genes (blue) and selfish genetic elements (gray) are maximized on Y chromosomes of intermediate age (maximum toxicity). Active transcription of Y-linked genes impedes heterochromatin formation at repeats that accumulate on degenerating Y chromosomes and their mobilization can create a mutational burden in males (middle). Selective pressure to efficiently silence a toxic Y chromosome and dosage compensation of the X homologs could drive adaptive degeneration of Y genes.
