Abstract
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Opsins are the photoreceptors of animal retinas [1]: vertebrate rhodopsin
is found in rod cells and mediates scotopic vision; red, green and blue
opsins are found in cone cells and mediate photopic vision. The opsins from
the lateral eyes and median ocelli of the horseshoe crab, Limulus polyphemus,
are likely to be the visible-wavelength rhodopsins in this animal [2]. In
the lateral eye, expression of the opsin gene is restricted to the photoreceptor cells of the ommatidia [2]. Limulus opsins, and closely-related
crayfish, mantid and honeybee rhodopsins, are most similar to the opsin
from the R1-6 photoreceptors of flies. |