A helix-loop-helix gene orchestrates male fate in common carp.

A helix-loop-helix gene called pangu is identified as the master sex-determining gene in common carp, controlling male development in this species.

• Why it matters: Understanding sex determination in fish like common carp is important because of their diverse mechanisms and the lack of a known master gene in the Cyprinidae family, which includes many species.
• What they did: Researchers used loss- and gain-of-function experiments, along with expression and reporter assays, to show that pangu is necessary and sufficient for male sex determination, and it represses the ovarian regulator cyp19a1a.
• The result: Disruption of cyp19a1a in pangu mutants restores testicular development, establishing pangu as the key gene linking HLH peptides to sex differentiation in common carp.