5α-Reductase Underscores the Development of Pectoral Fin Breeding Tubercles in Zebrafish
April 2026
in “
Communications Biology
”
TLDR The development of breeding tubercles in male zebrafish relies on a specific enzyme that processes hormones.
This study investigates the development of breeding tubercles (BTs) on the pectoral fins of male zebrafish, revealing that these structures are conserved in certain species within the Danioninae subfamily. The research identifies the gene srd5a2b, a paralog of steroid 5-α-reductase type 2, as a key regulator in BTs development. Experimental inhibition of this enzyme blocks BTs formation, while Dihydrotestosterone (DHT) treatment partially restores it, highlighting the importance of local androgen conversion. The findings suggest that localized androgen metabolism via the steroid 5-α-reductase pathway is crucial for the development and evolution of BTs as a secondary sexual trait in zebrafish.