OneManGang
Veteran
what defines when one species officially ends and another begins?
Well I'd say that since the DNA of humans would have to be altered significantly, the end product would have to be classified as a new species. The change would be so radical there would be no guarantee that humans could even breed with the end product, such would be the mutation to our genome to pull that off.
Phenotypically it would look very different as well. Our cells would have to have photosynthetic dye to trap photons, thus making us some wild color. I don't think we could be considered human at that point.