Why Is Mitochondrial DNA Important?

Are you interested in science, and do you want to know why is mitochondrial DNA important? Mitochondrial DNA is DNA that is located in organelles known as mitochondria. Mitochondira are structures within eukaryotic cells. They are vital because they convert energy from food into a type of energy that most cells can use. Yet, what is some more information about mitochondrial DNA, and why is mitochondrial DNA important?

Specifically, the mitochondria inside cells takes converted sugars from the food that we consume, and transform these sugars into a useable energy. Furthermore, the mitochondria make sure that the metabolism of the cell is regulated, the cell membrane potential is regulated, and the steroid synthesis is regulated.

Further, inside the mitochondria, there is DNA. In fact, the mitochondria has thirty seven genes within it. These genes are important to both ensure that the mitochondria is functioning properly and performing its important duties, as well as vital for the process of building proteins.

Mitochondiral DNA versus Nuclear DNA

Mitochondrial DNA and nuclear DNA are different from each other, and scientists think that they actually evolved separately. Scientists hypothesize that mitochondrial DNA evolved from circular genomes of the bacteria that were engulgued by earlier forms of eukaryotic cells.

In each mitochondrion, it is estimated that there are two to ten mtDNA copies. Most mitochondrial DNA is inherited from the mother. This is another difference between mitochondrial DNA and nuclear DNA. Nuclear DNA is inherited from both parents.

In humans, one hundred to ten thousand different copies of mtDNA are considered present in each cell (with the exception of egg cells and sperm cells). Thus, each double strand of mtDNA molecules contains approximately sixteen thousand base pairs.

As stated above, there are thirty seven genes of mitochondrial DNA. The two strands of mitochondrial DNA are separated into a “heavy” strand and a “light” strand. The differentiation refers to each strand’s nucleotides. The heavy strand has more guanine, and the light strand has more cytosine. The heavy strand is responsible for the encoding of twenty eight of the genes, and the light strand is responsible for the encoding of nine of the genes.

Why Is Mitochondrial DNA Important

So, then why is mitochondrial DNA important? Thirteen of the thirty seven genes of mitochondrial DNA are vital for the process of oxidative phosphorylation. The process of oxidative phosphorylation is the metabolic pathway in which energy released during the oxidation of nutrients is used to produce adenosine triphosphate (also known as ATP).

ATP is the molecule that is the main energy source for a cell. Virtually every form of life on earth has some type of process that produces ATP. Additionally, mitochondrial DNA is used in the process of creating transfer RNA (also known as tRNA) and creating ribosomal RNA (also known as rRNA). These two forms of RNA assist in transforming amino acids into proteins. Thus, mitochondrial DNA assist in two of the most important processes that occur in a cell.

Genetic Disorders

Unfortunately, because mitochondrial DNA are extremely important, there are a numer of genetic disorders associated with alterations in the mitochondrial DNA. Frequently, due to different types of cancers, mitochondrial DNA will be susceptible to somatic mutations.

Specifically, mutations in mitochondrial DNA has been seen in breast cancer, colon cancer, and liver cancer. Four different mitochondrial genes have also been linked to leber hereditary optic neuropathy. This condition is an inherited form of vision loss.

The four mitochondrial genes that have been linked to this condition are the following:

• MT-ND1
• MT-ND4
• MT-ND6
• MT-ND4L

The mutations that occur in the mitochondrial DNA affect how ATP is generated, and these effects result in reduced functioning in the optic nerve.

Mutations in two mitochondrial genes have also been linked to nonsyndromic deafness. Nonsyndromic deafness is a type of hearing loss that is not associated with any other syndromes. The two genes that are mutated and result in this disorder are MT-RNR1 and MT-TS1. These two genes are important in the process of making RNA.