“If opsins aren’t actually necessary to perceive colors, then we might need to expand how we define color sensitivity”
An eyeless worm has upended scientific understanding of color
▻https://www.inverse.com/science/eyeless-worms-can-still-see-color-study
This finding upends conventional scientific wisdom, which dictates organisms must possess the photoreceptor genes in opsins to discriminate between colors. C. elegans, remarkably, was able to discriminate between the colors despite lacking opsins.
The scientists also identified two sets of genes — chtl-1 and jkk-1 as well as F52H3.6 and lec-3 — that contribute to the roundworm’s avoidant responses to color, setting up the potential for future genetic research.
experiment, C. elegans
A figure from the study showing how the roundworm discriminates between colors to avoid danger. Dipon Ghosh et. al.
Why it matters — This roundworm’s color discrimination is no mere quirk, but an evolutionary gift, the researchers suggest.
“Our work also suggests that sensitivity to specific colors could offer some evolutionary benefit for the worm as it navigates an environment where it might encounter colorful microbes,” Ghosh says.
But Ghosh also believes the findings of the research go beyond roundworms, reshaping the way scientists think about the evolution of color discrimination. The work suggests opsins are not necessary for an animal to tell the difference between colors, for example. If opsins aren’t actually necessary to perceive colors, then we might need to expand how we define color sensitivity in other animals.
“Because it seems that worms have co-opted evolutionarily conserved genes for color sensitivity, we think our findings could generalize to other animals or even tissues that sense light, even if they don’t possess the classic molecules required for vision per se,” Ghosh says.
Microbial pigments might affect color perception in these other animals in a similar way to the roundworm, he adds.
“Perhaps microbial pigmentation can more generally affect foraging by wandering hosts other than C. elegans – meaning that colors might be involved in unexpected ways in other interspecies interactions as well,” Ghosh says.