CURRENT VIEWS ON EYE DEVELOPMENT

Several genes involved in the regulation of eye development in differe nt species have been identified. Structural and functional conservatio n have been found between some of these genes in organisms as diverse as Drosophila and mouse. One notable example is the relationship betwe en the mouse Pax6 gene and eyeless of Drosophila. Ectopic expression o f eyeless or mouse Pax6 in Drosophila results in the formation of addi tional eyes. Recently, another homeobox gene, Six3, was found to promo te ectopic lens formation in fish embryos. The next step will be to un ravel the associated regulatory pathways of these genes and assess the degree to which they display evolutionary conservation. This will be important in order to assimilate these findings with current anatomica l and embryological models. It seems reasonable to believe that in the near future the characterization of the whole framework required for vertebrate eye development will be accomplished.