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The DNA is read 3'->5' (and RNA synthesized 5'->3'). But due to the DNA strands having to be complementary, it seems to me that the origin can only appear on the correct side of the ORF on one of the strands. And even if it were possible to synthesise RNA from the other strand, due to the directionailty of the strands/RNA the RNA transcript would then code for the protein in reverse. Surely the reverse synthesis of a protein, even if containing all of the same amino acids, would lead to dfferent folding and thus only on eof the proteins is correct?

Now that I am considering the origin, it seems likely to me that the strand on which the origin is dictates which strand acts as the RNA template (perhaps both starnds can, however for a given GENE the RNA is always synthesised from the same strand.

Is this the case? I have read this post: Majority of transcripts are from sense strand? however I found it slightly confusing. I think what the answerer said is similar to what I have suggested here, however I am not quite sure. Would greatly appreciate some input.


marked as duplicate by David, Community Apr 15 '17 at 10:46

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    $\begingroup$ By "origin" do you mean "promotor"? You might wish to consult en.wikipedia.org/wiki/Promoter_(genetics) and then edit your question if appropriate and you feel it not answered in biology.stackexchange.com/questions/39046/…. $\endgroup$ – David Apr 15 '17 at 10:40
  • $\begingroup$ @David Thanks I did mean promoter! I realised when I re-read my question now- it is easy to get mixed up with the terms when learning about DNA replication and transcription simultaneously! As it transpires my question was answered in the post suggested by another 'Homo Sapien'. Thank you for your input. $\endgroup$ – 21joanna12 Apr 15 '17 at 10:46