Abstract
Our previous studies revealed that nuclear genome of rice (Oryza sativa, both Japonica and Indica varieties) contains multiple plastid and mitochondrial DNA (ptDNA and intDNA, respectively) splinters which altogether cover most of the organelle genomes and include intact copies of many organellar genes. In this paper, using the current annotations of nuclear genome of O.sativa japonica, we show that nuclear copies of five known plastid genes from rice have known cDNA that supports occurrence of their transcription in nucleus. So, nuclear copies of many organelle genes seem to be expressed in both genomes. Our findings suggest that, at least, some of these plastid genes represent candidates to be evolutionary transferred to nucleus and present an intermediate stage of organelle-to-nucleus gene transfer process that continues at present time. Moreover, it was found that 35 rice nuclear genes have orgDNA insertions in their coding exon(s), and some of these nuclear genes are complete copies of organellar genes. Analysis of these ptDNA insertions suggests some role of organellar sequences in both creation of novel genes and modifications of products of existing genes.