A limited number of genes are found in mitochondria beside nucleus. What's the difference between the genes found in mitochondria and nucleus.
Hello Muhammad Khan
The mitochondrial genome is transcribed and translated within the mitochondria, but the proteins required to carry out these processes are coded by genes present in the nuclear DNA. So, the genes in the nucleus affect gene expression in the mitochondria.
Another important difference between the genes in the nucleus and the mitochondria is that the mitochondrial DNA has a much higher rate of mutation (about 100-fold higher) than the nuclear DNA because it is subjected to damage from reactive oxygen molecules.
Also, mitochondrial DNA lacks DNA repair mechanisms which is found in nuclear DNA.
Best Wishes.
Dear Muhammad!
Mitochondrial vs. Nuclear DNA
Similar to the nuclear genome, the mitochondrial genome is built of double-stranded DNA, and it encodes genes (Figure 2). However, the mitochondrial genome differs from the nuclear genome in several ways (Taylor & Turnbull, 2005). Many interesting features distinguish human mitochondrial DNA from its nuclear counterpart, including the following:
- The mitochondrial genome is circular, whereas the nuclear genome is linear (Figure 3).
- The mitochondrial genome is built of 16,569 DNA base pairs, whereas the nuclear genome is made of 3.3 billion DNA base pairs.
- The mitochondrial genome contains 37 genes that encode 13 proteins, 22 tRNAs, and 2 rRNAs.
- The 13 mitochondrial gene-encoded proteins all instruct cells to produce protein subunits of the enzyme complexes of the oxidative phosphorylation system, which enables mitochondria to act as the powerhouses of our cells.
- The small mitochondrial genome is not able to independently produce all of the proteins needed for functionality; thus, mitochondria rely heavily on imported nuclear gene products.
- One mitochondrion contains dozens of copies of its mitochondrial genome. In addition, each cell contains numerous mitochondria. Therefore, a given cell can contain several thousand copies of its mitochondrial genome, but only one copy of its nuclear genome.📷📷Figure 3
- The mitochondrial genome is not enveloped, and is it not packaged into chromatin.
- The mitochondrial genome contains few, if any, noncoding DNA sequences. (Three percent of the mitochondrial genome is noncoding DNA, whereas 93% of the nuclear genome is noncoding DNA).
- Some mitochondrial coding sequences (triplet codons) do not follow the universal codon usage rules when they are translated into proteins.
- Some mitochondrial nucleotide bases exhibit functional overlap between two genes; in other words, the same nucleotide can sometimes function as both the last base of one gene and the first base of the next gene.
- The mitochondrial mode of inheritance is strictly maternal, whereas nuclear genomes are inherited equally from both parents. Therefore, mitochondria-associated disease mutations are also always inherited maternally.
- Mitochondrial genes on both DNA strands are transcribed in a polycistronic manner: Large mitochondrial mRNAs contain the instructions to build many different proteins, which are encoded one after the next along the mRNA. In contrast, nuclear genes are usually transcribed one at a time from their own mRNA.
- https://www.nature.com/scitable/topicpage/mtdna-and-mitochondrial-diseases-903/#:~:text=The%20mitochondrial%20genome%20is%20circular,22%20tRNAs%2C%20and%202%20rRNAs.
Mr. Alexandr has mentioned almost all, besides that you may like to know
Mitochondrial DNA codes for proteins of ETC and their DNA undergo division during mitotic division of cell they under go binary fission.
Recently many diseases including diabetes type 2,metabolic syndrome tuberculosis, cancer and thought to be mutations in Mitochondrial DNA, an interesting research area.
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