Fornetto C, Euler T, Baden T. Zebrafish use spectral information to suppress the visual background. Cell 188 1-17. direct link. pdf.
In brief
Vertebrate eyes first evolved in water, where spectral content rapidly fades with distance. Zebrafish exploit this loss by antagonizing cone signals to suppress the background, pointing to distance estimation—rather than color—as an ancestral cone function.
Highlights
- Zebrafish use fading spectral content in water to suppress visual background
- They do this by contrasting, not summing, inputs from distinct ancestral cone types
- Vertebrate cone diversity may reflect ancestrally aquatic ‘‘non-color’’ functions
- Mammalian cone loss may reflect rapid terrestrialization, not nocturnal ancestry