Question

Is mitochondrial DNA inherited from the father or mother?

Answer 1

Hint: Mitochondrial DNA is a small circular chromosome that is found inside the mitochondria of the cell. Mitochondria are important organelles found in the cell that is mainly the site of energy production. The DNA present in the mitochondria is passed onto the offspring from the parent.

Complete answer:
Mitochondria are semi autonomous cell organelles which are also called the powerhouse of the cell as they are centres of energy production through the Krebs cycle. They seldom arise de novo. Mitochondria occur through division of pre- existing mitochondria. Autonomy of mitochondria is due to their own DNA, replication, transcription and translation machinery.
Each mitochondrial has its own mtDNA and are usually naked. Each mtDNA is commonly circular and compacted to form a nucleoid. However, linear mtDNA is also known to occur in many cases. They usually operates independently as well as under the guidance of nuclear genes. In humans beings it code for 2 rRNAs, 22tRNAs, 13 proteins. It is small portion of the DNA that can be found in the eukaryotic cells; most of the DNA can be found in the cell nucleus.
Most of the multi-cellular mtDNA is inherited from the mother or we can use it as maternal inheritance. Mechanisms of this include around 200,000 mtDNA molecules. Healthy sperm of the male is reported to contains on average 5 molecules. mtDNA present in the sperm gets degraded in the male genital tract and in the fertilized egg with so exception in which it enters the egg without being degraded. The single parent, that is the mother, is found to inherit the DNA into the cell of the progeny. This helps in determining how a person have got a certain kind of disorder in the family. There are times when the disease that is inherited through the mother's line is opposed by both the parents. Because of this, family history is considered to know about from where the disease is inherited.
In exceptional cases, the newborn is sometimes found to contain both father and mother mtDNA, resulting in mtDNA heteroplasmy.

Note:
Human mitochondrial DNA was the first significant part of the human genome that was to be sequenced. Sequencing of it reveals that the human mtDNA includes 16,569 base pairs and 13 proteins.