While learning about DNA, we come across two main types: mitochondrial DNA and nuclear DNA. They are both completely different from each other and understanding each separately is very important. Messing these up could mess your understanding of genetics altogether!
Let’s learn about each one after the other and compare them to make this easy.
Nuclear DNA is present in all cells. The DNA has 46 chromosomes. 23 are inherited from the mother, and the remaining 23 are inherited from the father. Nuclear DNA has the nucleotides adenine, thymine, cytosine, and guanine. They are structured in a sequence, and any disturbance of the sequence can lead to dire and disturbing problems.
We can study the structure of DNA through the double helix model. The double helix separates into single strands during recombination.
Mitochondrial DNA or mtDNA
Mitochondrial DNA is only found in the mitochondria of cells. The biggest difference between nuclear DNA and mitochondrial DNA is the number of chromosomes. mtDNA only has one chromosome and codes only for a few proteins. This DNA is inherited only from the mother. The father plays absolutely no role in the transmission. Thus, recombination is not possible with mtDNA. mtDNA codes for proteins that are required during metabolism.
We use mitochondrial DNA for identification purposes.
Mitochondrial DNA vs Nuclear DNA
- Nuclear DNA has 99.75% of the genetic makeup while mtDNA only has 0.25%.
- While both are double stranded, mtDNA is circular while nuclear DNA is linear.
- mtDNA does not have histones, but nuclear DNA is packed with histones.
- mtDNA is inherited only from the mother, however nuclear DNA is inherited from both parents.
- The rate of mutation is much lower in nuclear DNA when compared to mtDNA.
- mtDNA has only one chromosome, but nuclear DNA has 46 chromosomes.
- mtDNA is always in a state of ploidy, but nuclear DNA is diploid.
- mtDNA has 16,569 DNA base pairs while nuclear DNA has 3.3 billion base pairs.
- mtDNA has 37 genes while nuclear DNA has around 25,000 genes.
- Nuclear DNA has a nuclear membrane. mtDNA does not have any membrane.
- mtDNA make rRNA and tRNA on their own while nuclear DNA does not.
- mtDNA does not change during the process of transmission from mother to child or offspring. Nuclear DNA undergoes a process called recombination.
- mtDNA genes do not have universal codon whereas nuclear DNA genes do.
- Non-coding sequences are present in nuclear DNA but not in mtDNA. In fact, 93% of nuclear DNA consists of non-coding sequences.
- There is a huge difference in the transcription of mtDNA and nuclear DNA. mtDNA is polycistronic while nuclear DNA is monocistronic.
Now you know just how different nuclear DNA and mtDNA are from each other. This should help you understand their working, importance, and features, making genetics easy and fun.
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