Does Mitochondria Have Circular DNA? 9 Facts You Should Know


Mitochondria are the organelles that have a bounded membrane making most of the energy needed by cell. Let us discuss about its specifically for mitochondria further on.

Mitochondria have circular DNA and is the smallest organelle to have cells. Mitochondria has a feature of making its own DNA . Mitochondria cannot have any other type of it. This is mostly done to have the DNA copied down for its work. This DNA helps in the genetic variation and it is linked via replication.

The DNA of the mitochondria is kept in small chromosome that is circular in its nature and thus DNA of the mitochondria is also circular. Let us get a better understanding about it further on.

Do mitochondria have DNA?

DNA is termed to be deoxyribonucleic acid and is said to be the hereditary of the organism it is present it. Let us discuss about it further.

This organelle has a very little amount of the DNA of its own seen in the nucleus and the mitochondria have circular DNA. It is vital in any organism and is the exclusive genetic substance seen in the mitochondria and is called to be the DNA or the mtDNA. All of the mitochondrial cells do have DNA.

Image credit-mtDNA from Wikipedia

All of the cells in the living body do have mitochondria as it gives out energy to the cell helping it function and making it worthy of letting itself be apart in the survival of the human.

Why do mitochondria have circular DNA?

The DNA of the mitochondria is specialized to perform functions with only either of the two being transferred. Let us understand about it.

The DNA of the mitochondria is tends to be circular for the small nucleoids. They have a circular copy of the DNA making it easy for itself to get copied for the smooth working of the cell and its generations. Both the heavy and light DNA are circular and are seen in the nucleoids.

The process of transcription in the mitochondria directs DNA to be copied in a manner same to that of replication and so needs nucleoid that are circular. For this, they have circular DNA.

What type of DNA is found in mitochondria?

The DNA of all the organism are kept in the chromosomes that are present in the nucleus and the mitochondria have a little for it. Let us discuss about it.

The genetic material are found in the mitochondria, is said to be circular, double stranded and two in nature as well. Thus this genetic substance is called as the mitochondrial DNA or mostly called as the mt DNA. It is same as the nuclear genome encoding many other genes needed and is in the small space.

Image credit-DNA from Wikipedia

On the contrary there is also a strand of DNA in them that is not double stranded. It is completely different from any other strand seen in any other organism. This DNA is single and links with proteins.

Why mitochondrial DNA is circular?

The circular type of DNA is mostly seen in the prokaryotes that comprise the bacteria and the archaea. Let us understand a bit about it.

Mitochondrial DNA is circularas it gets easily copied form the mother to the offspring during the method of replication. The DNA being circular is made from the loop of DNA that has no ends and is thus a closed loop. They are seen in chloroplast and are extrachromosomal.

The nucleus of the mitochondria does have circular nature connection to it which helps in storing the circular DNA. There is no membrane that blends this nucleus and thus needs to get protected.

Why is mtDNA important?

All of DNA is packaged in chromosomes, mitochondria also have a small amount of their own DNA. This genetic material is called mitochondrial DNA or mtDNA. Let us discuss.

In anthropological genetics, mtDNA is important to trace geographic distribution of genetic variation, for the investigation of expansions, migrations and other pattern of gene flow. mtDNA is widely applicated in forensic science. It is a powerful in implementing the identifying of human and its remains.

The mtDNA evolves faster than nuclear genetic markers, represents mainstay of phylogenetic and evolution. It interacts with the nuclear genome and is unexplored. This evolution is vital for organism..

Is mitochondrial DNA double helix?

Double helix, as related to genomics, is a term used to describe the physical structure of DNA. Let us discuss a bit about it.

The DNA of the mitochondria is of a double helical structure and with also having one that is stranded in single manner. Similar to the nuclear genome, the mitochondrial genome is built of double-stranded DNA, and it encodes genes. It is similar to the nuclear DNA in its form and also in nature.

Mitochondrial DNA or the mtDNA is a double-stranded molecule of 16.6 kb. The two strands of mtDNA differ in base composition, with one being rich in guanine by density. DNA spans for 16,500 blocks.

What are the differences between mitochondrial DNA and nuclear DNA?

Mitochondrial DNA, unlike nuclear DNA, is inherited from the mother, while nuclear DNA is inherited from both parents. Let us understand more about it.

CharacterNuclear DNAMitochondrial DNA
StorageStored in the nucleusSeen in the matrix of mitochondria
SizeThe size of it is 3200 mbIt has a size of about 16.6kb
DNA typeThis is linear and has strands that are anti parallel.It is circular and the DNA is double stranded
IntronThere is intron present.Mitochondrial DNA has no introns in them
Coding patternsThey have about 98% of the sequence linked to non-coding onesThere are less number of non-coding pattern being about 7%
TranscriptionThe type of transcription here is monogenicThe pattern for transcription here is multigene
Copy numberThe copy number is one per set of the cell from mother to progenyThe copy number here is 1000 per set of the cell from parents to offspring
Cell numberThe number of it per cell is about 46There are several thousand of them in the cells in all of the organism having them
Proteins presentThe linked proteins of these are the histones and the non-histonesThis do not have any proteins and are mostly said to be free of them
GenesThe encoding genes 30,000The number of genes encoded here are 37
Transcription mannerThe transcription here occurs in individual manner cell by cell and gene by geneThe transcription here occurs in bulk manner and not cell by cell but taking the entire strands at a go
CodonThe codon here is universalThey have mitochondrial codon
Difference between Mitochondrial DNA and Nuclear DNA

Nuclear DNA is DNA in cell nuclei and is responsible for the majority of functions that cells carry out. Mitochondrial DNA is associated with animals, plants and fungi, and comes from their own DNA. .

Which is absent in mitochondrial DNA?

During the course of fertilization event only nuclear DNA is transferred to the egg cell while rest all other things destroyed. Let us getting a brief about it.

The studies state the fact that cytosine methylation is virtually absent in mtDNA. In general the DNA lacks the presence of mature red blood cells. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. mtDNA is vital for all organism.

Image credit-Red blood cells from Wikipedia

The mtDNA also lacks the presence of many proteins at its base along with many other histones protein bases. Histone proteins act as spools around which DNA winds. Ribosomal protein genes are absent.

Is mitochondrial DNA single or double-stranded?

There is a report for the mitochondrial single-stranded DNA binding protein in regulating mitochondrial DNA replication initiation in mammalian mitochondria. Let us discuss it.

Mitochondrial DNA is a double-stranded molecule of 16.6 kb. Single stranded DNA is found in the bacteriophages. The single stranded DNA in these viruses is a cyclic molecule. The two strands of mtDNA differ in their base composition and one is light and the other is heavy for alkalinity.

Mitochondrial DNA, unlike nuclear DNA, is inherited from the mother, while later is inherited from both parents. It has circular molecule of 16569 bp and 37 genes coded to rRNAs, tRNAs and polypeptides.

Conclusion

Mitochondria have circular DNA and is the smallest organelle to have cells and having its own DNA that is circular. Mitochondria cannot have any other type of it.

ANKITA CHATTOPADHYAY

I am Ankita Chattopadhyay from Kharagpur. I have completed my B. Tech in Biotechnology from Amity University Kolkata. I am a Subject Matter Expert in Biotechnology. I have been keen in writing articles and also interested in Literature with having my writing published in a Biotech website and a book respectively. Along with these, I am also a Hodophile, a Cinephile and a foodie.

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