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This is an excerpt from a paper:

T>C mutations at NpTpN trinucleotides, also found in hepatocellular carcinomas, shows strong transcriptional strand bias with more T>C mutations on the transcribed than untranscribed strands

What exactly is meant by "transcribed" strand: the sense strand or the template strand ?

I tried looking up for it but couldn't find any definition.

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I think it should be the template strand . –  biogirl Jan 24 at 16:30
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i too guess that but am looking for a reference that defines so. –  WYSIWYG Jan 24 at 16:37
    
I also found this term being used in one of the leading A Level textbooks. –  biogirl Jan 26 at 13:54

2 Answers 2

up vote 2 down vote accepted

In my opinion they should mean the template strand, and they probably do. Perhaps if we had a link to the paper we could have examined the language more closely.

Here is a paper which uses the term in that sense:

Mugal, CF et al. (2008) Transcription-Induced Mutational Strand Bias and Its Effect on Substitution Rates in Human Genes. Molecular Biology and Evolution 26,131-142

In the abstract (which I have linked to) the authors make a clear reference to the transcribed strand in contrast to the coding strand (i.e. the strand of DNA with the same sequence as the RNA transcript):

All three [mutational rates] considered are found to be on average higher on the coding strand and lower on the transcribed strand...

There are also definitions confirming this at this Wikipedia page.

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Thanks.. I added the link to the paper. –  WYSIWYG Jan 24 at 17:49

Remember that DNA is double stranded and each strand has a chemical direction. Genes are read by the ribosome in the 3' to 5' direction so that the DNA 'forward' direction is defined in this direction. This is the direction of transcription.

Each segment of DNA can therefore be read in 2 directions. In the direction of transcription each T will have an A on the other strand. So each letter in the direction of transcription will not be the same if you read the other strand.

Transcription (that which is transcribed) refers to the ribosomal read strand.

Hope this helps.

enter image description here

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I understand that.. But when the authors say "transcribed strand" do they mean the strand that RNAPol reads or the strand that is actually in sense with the transcript ? –  WYSIWYG Jan 24 at 16:11
    
transcription (that which is transcribed) is the ribosomal read strand. i'll put that in the answer too... –  shigeta Jan 24 at 18:24

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