Evolución de Ojos y Fotorreceptores

MARIO E. GUIDO; PEDRO PANZETTA

Oftalmologia Clinica y Experimental

Consejo Argentino de Oftalmología

Lugar: Buenos Aires; Año: 2008 vol. 2 p. 27 - 32

1851-2658

Perhaps, the most spectacular identification of a biological function in nature can be observed in the eye (1). Darwin was fascinated with the fact that how such a perfect organ like the eye could have evolved gradually (2); indeed, the most ancient step in the sequence that guided to its formation was just a spot in the dermis capable of detecting light. Such a very rudimentary structure had this selective advantage from the beginning and any additional modification improving its functioning, would be favored by evolution. Then, not only the complex eyes are useful in nature; in fact, many different animals have simple eyes which are adequate for light detection: these simple eyes are good enough to assure survival and reproduction.  In this short review, we discuss some aspects regarding the evolution of eyes and photoreceptors in the living organisms in relation to new discoveries and intriguing lines of thought and trends based on morphology, specification markers, opsins and photosensitivity involving  a number of processes highly conserved through the evolution.