Cells in human body consist of many small organs or subunits that have specific functions. Mitochondria are one such subunit whose prime responsibility is to translate the energy received from food into a utilizable form for cells. However, unlike other subunits found in cells, mitochondria have genetic information of their own, which is known as Mitochindrial DNA.
Human beings have almost 16.500 base pairs of DNA that form the Mitochondrial DNA. However this is only a fraction of total DNA found in the cells of human body of which most is located within the nucleus in chromosomes.
All in all, there are 37 genes enclosed in the Mitochondrial DNA and in order for the Mitochondria of cells to function perfectly, all of these are of essence. According to the function that these genes present inside Mitochondrial DNA perform, they can be divided into two groups. The first group consists of 13 genes. These are responsible for providing the right directives for the production of enzymes that carry out oxidative phosphorylation, a process that produces the main supply of energy for the cell via making use of oxygen and sugar.
The second group of genes present in Mitochondrial DNA is responsible for laying out the foundations of a number of RNA molecules, transfer RNA’s and ribosomal RNA’s to be more precise. These RNA’s function similar to the DNA except the fact that they work outside the protected membrane and help in building proteins for the body.
It is interesting to note that Mitochondrial DNA can only be inherited from one’s mother. Though sons and daughters both inherit it from their mother, only daughters can pass it to their next generation.
A maternal lineage test, examines an individual’s biological relatedness to his or her maternal family. The test is conducted through a sequence analysis of Mitochondrial DNA.
The changes, also known as mutations, in the structure of Mitochondrial DNA are often associated with many diseases, of which cancer is also one. Factors that cause Somatic mutations, i.e. changes that are not inherited by the next generation, affect Mitochondrial DNA somewhat easily. This mutation may cause cancer affecting many parts of the body including liver, kidney, stomach etc as well as leukemia and lymphoma.
Somatic mutations attack the self-repairing mechanism of Mitochondrial DNA via the over production of dangerous molecules that are known as reactive oxygen species. It is these harmful molecules that Mitochondrial DNA is quite defenseless against.