Difference between Mitochondrial DNA and Chloroplast DNA

The organelle genetic system of mitochondria and chloroplasts has been stipulated to arise from prokaryotic bacteria around 1 million years ago. The endosymbiotic theory says that eukaryotes started as anaerobic organisms without mitochondria; they then established endosymbiotic relations with the bacteria and subverted their oxidative phosphorylation machinery for their own use. Through this endocytosis event, the eukaryotes gained the mitochondrial structure from the bacteria.

Similarly, chloroplasts were gained in another endosymbiotic event from bacteria to the plants.

Mitochondrial and chloroplast DNA are extranuclear DNA present in the cells apart from the nuclear genome.

While the genes in chloroplasts participate in photosynthesis, the mitochondrial genes are known to take part in oxidative phosphorylation and protein synthesis.

Mitochondrial DNA vs Chloroplast DNA

Mitochondrial DNA

Chloroplast DNA


Mitochondrial DNA is the DNA found in the mitochondria of all eukaryotes.

Chloroplast DNA is the DNA found in the chloroplast of plant cells.



cpDNA or plastome

Size of the Genome

It is about 16,500 base pairs in size.

The genome size of chloroplast DNA is 70,000 to 200,000 base pairs.

Shape of the DNA

It is both circular and linear.

It is only circular. (Linear DNA is seen in exceptional cases)

Number of Genes




The genes in the mitochondrial DNA take part in oxidative phosphorylation for the production of ATPs and in the synthesis of proteins.

The chloroplast genes participate in photosynthesis in plants.

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Frequently Asked Questions on Difference between Mitochondrial DNA and Chloroplast DNA

What are the differences between mitochondrial DNA and nuclear DNA?

Mitochondrial DNA is not densely packed into chromosomes, and the genes replicate to produce proteins that work only for the mitochondria. On the other hand, nuclear DNA is densely packed into chromosomes and the proteins that are synthesised work for the entire cell.

How is DNA in chloroplast different to DNA in the nucleus?

Nuclear DNA is long, linear and associated with histone proteins, whereas chloroplast DNA is smaller, circular and not associated with histones.

Why do mitochondria and chloroplast have DNA?

There is no proven evidence that suggests the reason for the retention of DNA in chloroplast and mitochondria.

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