Evolution of the Eye

Comparative anatomists have discovered numerous intermediates between this most primitive type of eye and the vertebrate eye, such as: eye cups; pinhole eyes; camera-type eyes with a single lens; reflecting mirror eyes; and compound eyes with numerous ommatidia, all of which lends support to Darwin’s theory.

A monophyletic origin for the eye is supported by the observation that all metazoans share the same visual pigment, rhodopsin

The observation that Pax 6 homologs of both mammals and insects are essential for eye morphogenesis led to the idea that Pax 6 might be the universal master control gene for eye morphogenesis and evolution

The protein-coding regions of Pax 6 are highly conserved in evolution, as are some of the regulatory sequences in the promoters and enhancers.