Genetic Codes

Keith Robison robison1 at
Wed Apr 7 07:57:25 EST 1993

abigail at (Shawn Abigail) writes:

>I downloaded the list of genetic codes (SGC0, SGC1, etc), but I have
>one question.  Do all of the codes listed recognize AUG as an
>initiation codon?  Some of the codes do not list any initiation
>codons (does this mean AUG is accepted?), some list alternate
>initiation codons (does this mean that AUG is also acceptable?) and
>some list alternates and AUG (this really confuses me, because I
>would not expect to see AUG listed if it was implied).  Thanks for
>any help you can provide, because there is nobody here at my university
>that can help me with this.

>Shawn Abigail
>abigail at

I don't have a reference for this (and I need one too!) but the
general rules are:

	1) Eukaryote nuclei use only AUG, translated as Met.
	2) Bacteria use AUG mostly, but GUG, CUG, and UUG sometimes.
	   It is always translated to fMet.
	3) Some mitochondria use a whole host of initiators, but
	   still translate them to Met.
	4) Chloroplast genes use AUG translated as Met, but in
	   some cases the AUG is created through RNA editing.

Any corrections/additions/expansions will be appreciated -- I'm doing
this all from (error-prone) memory.

It's sort of a wierd place to look, and they have some subtle errors,
but one place that has these listed is the documentation for NCBI's
ASN.1 Tool Library, available via FTP from

Keith Robison
Harvard University
Department of Cellular and Developmental Biology
Department of Genetics / HHMI

robison at 

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