0
$\begingroup$

DNA has transcribed into RNA (Non-coding). Can this RNA mutate and become a Protein-Coding one/mRNA? Have there been any such instances reported by scientists?

$\endgroup$
  • $\begingroup$ The ncRNA will be transcribed from nuclear genomic DNA. Therefore the mutagenic events would take place in the DNA that codes for that ncRNA gene. It has nothing to do with the relative chemical stability of the different types of nucleic acids. There are viruses with RNA genomes, that do not require a DNA intermediate for replication, like Q-Beta, which codes for its own RNA-based RNA polymerase (as I recall). Are you familiar with the so-called "Central Dogma" of molecular biology? DNA makes RNA. RNA makes Protein (or in this case, the RNA does not code for a protein). $\endgroup$ – mdperry May 13 '16 at 10:32
  • $\begingroup$ @mdperry Let me rephrase it: Can a ncRNA (transcribed product from DNA) convert into a mRNA? By mutation, I mean mutation in RNA, not in the DNA which makes that RNA (as it has already transcribed now) $\endgroup$ – Failed Scientist May 13 '16 at 12:13
  • $\begingroup$ If you had a gene that mutated its start codon or something, so that it was still transcribed, but the RNA could not be translated, that could be considered ncRNA. If that mutant gene had another mutation that fixed the original error, it might be translated again and become a coding RNA. But mRNAs typically need a start codon, kozak sequence, etc. These features would be hard to find on a ncRNA that didn't originate from a mutated gene. $\endgroup$ – user137 May 13 '16 at 12:49
  • $\begingroup$ @user137 Thanks! I got you! Yeah it seems highly unlikely to have that much modifications/mutations to ncRNA. You made an interesting statement in start of your comment. Can you please explain it further (start codon or something)? $\endgroup$ – Failed Scientist May 13 '16 at 12:57
1
$\begingroup$

Answers

  1. Possibly, but with such a low frequency as to be unimportant and undetectable. (Monkeys with typewriters producing Shakespeare’s Hamlet comes to mind.)

  2. No. Because it would be extremely difficult to detect, it would seem to be of no importance if it did occur at a very low frequency (you make no suggestion of why it would be of interest) and therefore there would be no reason for anyone to try.

Why would it be difficult to detect?

The difference between mutations that occur in DNA and any that might occur in RNA, is that a mutation in DNA can give rise to a population (e.g. of bacteria, or offspring) all of which carry the mutation. Thus, even though the chance of the particular mutation may be very low (say 1 in a million or less), a situation can arise in which the whole population is producing the RNA transcribed from the mutated gene and the protein encoded by the RNA. If RNA mutation occurs with the same frequency and managed to change a non-coding RNA (perhaps a pseudogene with a frameshift) to a coding RNA, only 1 in a million transcripts would be changed. Therefore if one sequenced the RNA the incidence of such changed RNA would be too low to detect, or if detected would be below the error margin in such experimental work.

Why has nobody looked for it?

Experimental science costs time and money. Scientists explore theories that have an importance and probability of success that attracts competitive funding. If there is no particular reason to look for something and the chances of seeing it are minute, nobody will waste their time on it, and they would certainly not get funded to do so.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.