MEIOSIN retains a STRA8-independent activity that contributes to meiotic gene activation across vertebrates.

MEIOSIN independently activates meiotic genes across vertebrates, including species lacking STRA8, by retaining an HMG domain essential for this function.

• Why it matters: Understanding the ancestral mechanisms of meiotic regulation is crucial, as it reveals how different vertebrate lineages have evolved distinct genetic controls for meiosis, impacting reproductive biology.
• What they did: The study used comparative genomics, genetic, and single-cell analyses in zebrafish and mice to investigate MEIOSIN's activity, identifying orthologs in species without Stra8 and analyzing domain structures and functions.
• The result: Findings show MEIOSIN's HMG domain supports meiotic gene activation independently of STRA8, with loss of MEIOSIN disrupting female germline development in zebrafish and partially impairing meiosis in mice, suggesting a conserved core mechanism.