Ah, I was just writing about the evolution of color vision and this interesting article came across my Twitter (via Ed Yong): "The humans with super human vision".
What would it be like to see through cDa29’s eyes? Unfortunately, she cannot describe how her color vision compares with ours, any more than we can describe to a dichromatic person what red looks like. “This private perception is what everybody is curious about,” Jordan says. “I would love to see that.” Jordan’s next challenge is discovering why cDa29 is different from the other women she tested. “We now know tetrachromacy exists,” Jordan says. “But we don’t know what allows someone to become functionally tetrachromatic, when most four-coned women aren’t.”
Potential tetrachromats are female relatives of colorblind males, based on the presence of a fraction of mutant cones. I'd be more interested in knowing about more extreme tetrachromats, who may have allelic dimorphism in any of the normal three beyond the normal trichromatic range.