Multiple Reading Frames in DNA

David B. Hedrick davidbhedrick at
Sat Apr 12 12:43:50 EST 1997

Tim Taylor wrote:
> Hi,
> As a non-biologist, I have a small question which I hope someone
> can give me a quick answer to.
> I'm sure I've read in the dim and distant past that the DNA of
> some organisms includes sections which are transcribed multiple
> times starting from different bases (different reading frames).
> These therefore get translated into completely different
> proteins, so the genome is encoding multiple messages in the
> same bit of DNA.
> Can someone tell me what this phenomenon is called (if it has a
> special name), and give me an example (with a reference to a
> book, paper etc. if at all possible)?
> Thanks in advance,
> Tim
> --------------------------------------------------------------------------
> Tim Taylor, Department of Artificial Intelligence, University of
> Edinburgh
>             tel (+44)-131-650-3081 or -650-4493  fax -650-6899
>                 web

Hello, Tim:

	You got it - "multiple reading frames".  

	Remember that the 2 strands of DNA are anti-parallel.  If one strand is
read from left to right, the other is read from right to left.  Some
genes in eukaryotes (multi-cellular critters like us) can give different
products by being transcribed beginning at different starting points or
by terminating transcription at different points.  The really
mind-blowing example comes from viruses.  Since the selection pressure
on them is very great to reduce the size of their genome, viruses often
code for 2 different proteins on the same section of DNA!  One from each
of the 2 strands.  To see how complex this is, imagine that you wrote me
a note that gave one message, and another different message when looked
at in a mirror.  
	Any textbook in molecular biology should give you several examples.  

Technical writing, literature search, and data analysis at the interface
of chemistry and biology. 

	davidbhedrick at

	David B. Hedrick
	P.O. Box 16082
	Knoxville, TN 37996

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