Gene duplication, transfer, and evolution in the chloroplast genome

In addition to the nuclear genome, organisms have organelle genomes. Most of the DNA present in eukaryotic organisms is located in the cell nucleus. Chloroplasts have independent genomes which are inherited from the mother. Duplicated genes are common in the genomes of all organisms. It is believed that gene duplication is the most important step for the origin of genetic variation, leading to the creation of new genes and new gene functions. Despite the fact that extensive gene duplications are rare among the chloroplast genome, gene duplication in the chloroplast genome is an essential source of new genetic functions and a mechanism of neo-evolution. The events of gene transfer between the chloroplast genome and nuclear genome via duplication and subsequent recombination are important processes in evolution. The duplicated gene or genome in the nucleus has been the subject of several recent reviews. In this review, we will briefly summarize gene duplication and evolution in the chloroplast genome. Also, we will provide an overview of gene transfer events between chloroplast and nuclear genomes.