Tetrachromat Vision (4-Base Color in Humans)
Apparently in women only, 4-Base Color in Humans and still needs research to understand and confirm the claims. JOV claims:
Some 12% of women are carriers of the mild, X-linked forms of color vision deficiencies called “anomalous trichromacy.” Owing to random X chromosome inactivation, their retinae must contain four classes of cone rather than the normal three; and it has previously been speculated that these female carriers might be tetrachromatic, capable of discriminating spectral stimuli that are indistinguishable to the normal trichromat.
