There is a dramatic difference between a dark-grown plant and a plant that has been exposed to even small amounts of light. Specific quantities, qualities and combinations of light energies can lead to profound changes in gene expression that  affect specific facets of plant development.  My laboratory has implemented genomic technologies and unique measurement techniques to dissect the process of photomorphogenesis in the model plant Arabidopsis thaliana. Using this approach, we have characterized physiological effects of green light during seedling development that cannot be attributed to known light-sensing systems. In conjunction with a bioinformatics approach, we have shown that these responses correspond to unusual patterns of gene expression and have identified specific genes that are affected by green light. In general, green light responses antagonize those mediated by blue and red wavebands, and we are currently investigating the transduction schemes that mediate these responses.