Editors' ChoiceEVOLUTION

Eye of Lizard

Science's STKE  21 Mar 2006:
Vol. 2006, Issue 327, pp. tw104
DOI: 10.1126/stke.3272006tw104

The parietal eye of lizards responds to light and dark but does not form images. Su et al. show that blue light and green light, working through opsins unlike those in visual eyes, send antagonistic signals to a key cyclic guanosine monophosphate (cGMP) phosphodiesterase. Subsequent alterations in cGMP concentrations modulate channel openings to depolarize or hyperpolarize the parietal photoreceptor cells. Comparison of the opsins and signaling molecules involved suggests an evolutionary trajectory by which the parietal eye diverged from the visual eyes.

C.-Y. Su, D.-G. Luo, A. Terakita, Y. Shichida, H.-W. Liao, M. A. Kazmi, T. P. Sakmar, K.-W. Yau, Parietal-eye phototransduction components and their potential evolutionary implications. Science 311, 1617-1621 (2006). [Abstract] [Full Text]