Abstract
After the endosymbiosis, a lot of genes encoded by the chloroplast genome have been transferred to the nuclear genome. This gene transfer event has been occurred by following steps. (1) Endosymbiosis, (2) Chloroplast DNA was transferred to the host nucleus and integrated into the nuclear genome, (3) Transferred genes were obtained the expression system in the nucleus, and also obtained the transit peptide to chloroplasts, and (4) Orthologus genes remained in the chloroplast genome were removed. As far as we know, there are no plants that orthologous genes encoded by both chloroplast- and nuclear-genome are functional simultaneously in the chloroplast. In many higher plants, the gene for 30S ribosomal subunit S16, rps16, is encoded not only by the chloroplast genome but also by the nuclear genome, and nuclear-encoded S16 protein is targeted to chloroplasts. Here, we analyzed whether the chloroplast-encoded rps16 gene is functional in chloroplasts using tobacco as a model.
