Scientists finally found the exact 'kill switch' in the DNA of cave fish that tells their bodies to just stop growing eyes.
April 13, 2026
Original Paper
Long-term hybridization in a karst window reveals the genetic basis of eye loss in cavefish
bioRxiv · 2024.10.25.620266
The Takeaway
It has been a mystery for decades why animals in total darkness give up their sight. By pinpointing a single protein mutation, researchers proved how evolution systematically shuts down the visual system when it's no longer needed.
From the abstract
Eye loss is a hallmark trait of animals inhabiting perpetual darkness, yet the precise genetic variants underlying this evolutionary change remain largely unknown. The Mexican tetra (Astyanax mexicanus) provides a powerful model for dissecting the genetic basis of eye degeneration, as sighted surface fish and multiple independently evolved blind cave populations remain interfertile; yet despite decades of research and numerous QTL studies, the genetic basis of eye loss has remained unresolved at