cpDNA

Chloroplasts, the organelles responsible for photosynthesis in plants and algae, contain their own small, circular chromosomes called extranuclear DNA, or cpDNA. This cpDNA holds genes essential for photosynthesis and other chloroplast functions.1

The genetic information for the photosynthetic apparatus is distributed between the chloroplast's DNA and the cell's nucleus. For instance, the genes for large subunits of a key photosynthetic enzyme are in the chloroplast, while genes for small subunits are in the nucleus. This dual genetic control highlights the complex interplay between chloroplasts and the rest of the cell, with chloroplasts potentially influencing the expression of nuclear genes involved in their function. It is believed that chloroplasts, like mitochondria, evolved from free-living cyanobacteria, which may explain their distinct DNA.21