I was researching mutations and came across an interesting question: Do mutations occur in the DNA or mRNA of an organism? Is this more opinion that science?
Thanks in advance!
DNA. mRNA is transcribed from DNA.
A mutation is the permanent alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.
The key word here is genome. A mutation is defined as something occurring in the genome, and the genome of living beings is made of DNA. Hence, mutations arise in the DNA.
A special case concerns viruses (which, for the record, are often not considered living beings): they can have a RNA genome, so they can have mutations in the RNA.
This does not mean that mRNA transcription is an error-free process! As an example, this link gives you a nice overview on the error rate in transcription and translation,which apparently are quite high. It's just that, by definition, mutations arise in the genome.