Deoxyribonucleic acid is abbreviated as DNA. DNA is a complex molecule as long as three billion letters. It contains pieces of information that distinguish a living organism from another. The features of a living being are dependent on the pieces of information. Each one of us possesses a unique DNA.
Mitochondrial DNA vs Nuclear DNA
The main difference between mitochondrial DNA and nuclear DNA is that mitochondrial DNA is localized inside the mitochondria while nuclear DNA is centered within the nucleus of the cell. The mitochondrial DNA is extremely minute in contrast to the nuclear DNA, which is massive. The mitochondrial DNA is often recognized as the maternal DNA due to its inheritance traits from the mother.
Mitochondrial DNA is found inside the mitochondria along with ribosomes. Ribosomes are responsible for the production of protein. The size of the mitochondrial DNA is 16,569 bp. The mitochondrial DNA is cellular in shape, they are different from those of nuclear DNA. The mitochondrial DNA is the result of an evolution that took place one and a half billion years ago. The mitochondrial DNA has the self-replicating capability.
The nuclear DNA is situated in the nucleus of the cell. It depicts a rod-like structure. The nuclear DNA was first observed by Friedrich Miescher in the year 1869. Since then a new horizon that deals with genetics came into studies. Nuclear DNA is huge, they are around three hundred billion letters long. They contain all the genetic pieces of information of an individual and monitors all the functions that initiate in the human cell.
Comparison Table Between Mitochondrial DNA and Nuclear DNA
| Parameters of comparison | Mitochondrial DNA | Nuclear DNA |
| Definition | DNA present inside the mitochondria is known as mitochondrial DNA. | DNA in the nucleus of the cell is called nuclear DNA. |
| Structure | It has a circular structure that does not resemble nuclear DNA. | Linear or rod-like structure. |
| Size | 16,569 bp | 3.3109bp |
| Density of gene | One per four hundred fifty bp | One per forty thousand bp |
| Percent of coding DNA | 93% | 3% |
What is Mitochondrial DNA?
Mitochondria is the source of the energy of our cells. The number of mitochondria varies from cell to cell. In other words, cells that are capable to execute more energy contain more mitochondria than those cells that require lesser energy to perform.
If we magnify the structure of mitochondria we can see it consists of an outer membrane, an inner membrane. Inside the inner membrane, we find DNA as well as ribosomes. Due to the presence of ribosomes (protein factories) and DNA within the mitochondria, it can initiate protein synthesis. Genetic materials are present in the nucleus of the cell, while here we find mitochondria have their DNA (genetic pieces of information). Thus mitochondria can replicate themselves.
Evolution (which took place 1.5 billion years ago) is the reason behind the presence of mitochondrial DNA (maternal DNA). The theory of endosymbiosis states that initially, mitochondria was a prokaryotic cell. When the prokaryotic cell was engulfed by the eukaryotic cell, a symbiotic relationship was established between them. The DNA within the mitochondria is the mitochondrial DNA. The mitochondrial DNA is circular. The mitochondrial DNA is sixteen thousand letters long. One percent of the cellular DNA is mitochondrial DNA. Mitochondrial DNA is composed of light and heavy strands.
What is Nuclear DNA?
Our body is made up of billions of cells, an animal cell lacks a cell wall. We are eukaryotic beings. Each cell has its nucleus and the nucleus is the home of DNA. The DNA present in the nucleus of the cell is nuclear DNA. Each individual has a unique set of DNA that differentiates them from another individual. The concept of DNA was initiated in 1869 by Friedrich Miescher. With the introduction of DNA, we were able to unfold in the mysterious world of genetics.
DNA initiates and plans all the functions of the cell, it is considered the head of the cell. The twisted ladder-shaped DNA termed as double helix implies DNA is a polymer. So polymers are an accumulation of repeated monomers. These monomeric units are glucose molecules and each of the glucose units is bonded via glucosidic bonds. DNA stores all the pieces of information of an individual. It plays a pivotal role in the functioning of the cells. Living organism reflects the genetic traits of their unique DNA. Our skin color, the color of our eyes, our height, and other relative features are the result of the genetic pieces of information our DNA contains. The nuclear DNA is as large as three million letters.
Main Differences Between Mitochondrial DNA and Nuclear DNA
- The mitochondrial DNA encodes only thirty-seven genes whereas the nuclear DNA encodes twenty thousand to thirty thousand genes.
- The mitochondrial gene is sixteen thousand letters long. The nuclear DNA is three billion letters long.
- The mitochondrial DNA does not contain histone proteins, whereas the nuclear DNA contains histone as well as non-histone proteins.
- The mitochondrial DNA depicts maternal inheritance whereas the nuclear DNA shows mendelian inheritance and parental inheritance.
- The mitochondrial DNA is present in the mitochondria while the nuclear DNA is situated in the nucleus of the cell.
- The gene density in the mitochondrial DNA is one to four hundred and fifty base-pair whereas gene density in nuclear DNA is one per forty thousand base pairs.
Conclusion
The mitochondrial DNA and the nuclear DNA show significant differences in location, functions, and structure. The mitochondrial DNA is small enough in contrast to the nuclear DNA. The mitochondrial DNA is situated in the mitochondria whereas the nuclear DNA is situated in the nucleus of the cell. The mitochondrial DNA is self-replicating. The nuclear DNA on the other hand governs all the functions that occur within the cell. The mitochondrial DNA mutates twenty times speedier than nuclear DNA. The shape of the mitochondrial is more or less like a circle whereas the nuclear DNA is linearly shaped.
References
- https://www.pnas.org/content/83/23/9090.short
- https://www.pnas.org/content/80/21/6495.short