Rapid protamine evolution suppresses meiotic drive in Drosophila.

Rapid evolution of protamines in Drosophila suppresses sex chromosome meiotic drive, with Mst77F playing a key protective role against sex ratio distortion.

• Why it matters: Understanding why protamines evolve so quickly is crucial because they are vital for sperm function and fertility, yet their rapid change suggests an underlying evolutionary pressure that remains unclear.
• What they did: The study used in vivo gene replacement to swap Mst77F orthologs in D. melanogaster, revealing DNA compaction defects and sex ratio biases, and tested the role of Mst77F in D. yakuba for comparison.
• The result: Findings demonstrate that the rapid evolution of protamines is driven by the need to suppress sex chromosome meiotic drive, enabling species to maintain balanced sex ratios and fertility.