The genetic control of eye development and its implications for the evolution of the various eye-types

Int J Dev Biol. 2002 Jan;46(1):65-73.


Mutations in the Pax 6 homologs of mammals and insects prevent eye development and targeted expression of both mammal and insect Pax 6 homologs is capable of inducing functional ectopic eyes. Supported by RNA interference experiments in planarians and nemerteans, these findings indicate that Pax 6 is a universal master control gene for eye morphogenesis. Since all metazoan eyes use rhodopsin as a photoreceptor molecule and the same master control gene for eye development, we postulate a monophyletic origin of the various eye types. The finding of well developed eyes in jellyfish which essentially lack a brain, leads us to propose that the eye as a sensory organ evolved before the brain which is an information processing organ. The finding of highly developed eyes with a lens, vitreous body, stacked membranes like a retina and shielding pigment in unicellular dinoflagellates, raises the possibility that the prototypic eyes might have been acquired from symbionts.

Publication types

  • Review

MeSH terms

  • Animals
  • Eye / embryology*
  • Eye Proteins
  • Gene Expression Regulation, Developmental
  • Homeodomain Proteins / metabolism
  • Models, Biological
  • Mutation*
  • Ocular Physiological Phenomena*
  • Oligonucleotide Array Sequence Analysis
  • PAX6 Transcription Factor
  • Paired Box Transcription Factors
  • RNA / metabolism
  • Repressor Proteins


  • Eye Proteins
  • Homeodomain Proteins
  • PAX6 Transcription Factor
  • Paired Box Transcription Factors
  • Repressor Proteins
  • RNA