DNA Nomenclature

Enrique Jose Labadan Frio - SCBC - 3421101 g3421101 at MUCC.MAHIDOL.AC.TH
Sat Mar 5 01:11:27 EST 1994

On 4 Mar 1994, Dr. M.D. Jones wrote:

> DNA (usually) is double stranded. > One DNA strand is identical in
sequence to mRNA.  This is called the non-coding > strand or sense strand.
> The other complementary strand is thus the coding strand or anti-sense
strand. > > I presume this comes about from the fact that the 'coding'
strand acts the > template for the RNA polymerase to produce the mRNA. > >
Unfortunately to my mind, I find it logically to call it the reverse.  In
that > the mRNA carries the coding information, and the DNA strand that is
equivalent > to this should be the coding strand, but this is usually
refered to as the > 'non-coding'. > > Confusing eh :-)


	Several authors of Biochemistry textbooks AFAIK do address this
*confusing* problem. Voet and Voet (Biochemistry) describe the mRNA coding
strand of DNA as the "sense" strand, but Lewin (Genes IV) ascribes the
term to the non-coding strand (hence, the mRNA coding strand is the
"antisense"). Literature started following these terminology more closely
upon the advent of the so-called "antisense" oligos used for blocking mRNA

	It all boils down, in my opinion, as to what the word "SENSE" 
would mean to people, and to which entity the code makes "sense"; to 

	Does "sense" point to the RNA polymerase or to the ribosome?
	In other words, to which do we attribute the word "sense" to - 
the RNA pol, or the ribosome?

	Two schools of thought do tend to argue about this: the "mRNA-
coding strand is anti-sense" group tend to argue that the mRNA code is
read by the ribosome (ie, genetic CODE when TRANSLATED by the ribosome
makes SENSE as protein); hence, the non-mRNA-coding strand (the mRNA
coding strand's complement) is the sense strand. 

	The other group ("mRNA-coding strand is anti-sense") contends that
it is the RNA pol which makes "sense" out of DNA, so the mRNA coding
strand is the sense strand. 

	Confused? Yup, it happens to the best of us. Things like these in
the literature would tend to bog us down in misunderstandings and it would
really be great if this matter can be resolved. 

	Otherwise, why not call the strands with more distinctive names,
like Watson and Crick (actually, the double Helix has their names on it in
honor of their discovery, though I could never remember to which strand
the two great scientists are assigned). Alternatives would be mRNA-CS and 
mRNA-NCS. Or as they concluded after the new name search for the Big 
Bang, nothing really beats the original...(though in this case, we don't 
know which term is the original one).

	Hope we can compile people's thoughts on these....

{All of these are my opinions --- standard disclaimers apply}

Querix Frio			
Dept of Biochemistry		
Mahidol University
Bangkok, Thailand

g3421101 at mucc.mahidol.ac.th

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