[EMBOSS] CAI Tables
Tamas Hegedus
hegedus at biomembrane.hu
Tue Dec 20 13:17:18 UTC 2005
Hi,
I am not a CAI expert; I also could not find one around me; reading was
not enough for me in this topic.
So I would like to take the opportunity to ask a CAI (not EMBOSS)
related question.
What can you tell me about human (mammalian) CAI tables?
What do you think/know about the FOP values introduced by Lavner & Kotlar?
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15716084&query_hl=1
I would like to use some measure to predict the translation speed of
certain regions in some proteins I am interested in.
Thanks,
Tamas
Peter Rice wrote:
> Kevin Brown wrote:
>
>
>>I've searched the archives and the Net trying to find more information
>>the list of highly-expressed genes that CAI used to create the codon
>>tables for the various species. Does anyone know where these tables
>>came from?
>
>
> Well, it is a long story ...
>
> The original CAI (Codon Adaptation Index) was calculated for S. cerevisiae and
> used a set of 24 genes (ribosomal proteins, for example) that were known to be
> highly expressed.
>
> Many years ago when I wrote a program to calculate the codon usage for S.
> pombe (fission yeast) in a program called "codfish", I created a table for the
> few S. pombe genes from the same set that had already been sequenced.
>
> On arriving at the Sanger Centre, where they were sequencing a lot of S.
> cerevisiae, I needed the codon usage table for the original CAI - and found
> that when I used the current gene sequences I got the wrong answer.
>
> After some tweaking I was able to reconstruct the original versions of the
> cerevisiae sequences and could reproduce the "standard" CAI values. The
> differences were minor - mainly missed short 5' exons.
>
> The tables Eyeast_cai.cod and Eschpo_cai.cut are the result of these two
> tables. There are, for historic reasons, copies of these tables with no
> headers and different names which are "obsolete" and will disappear in EMBOSS
> 4.0.0.
>
> As for "codfish" ... it implemented an algorithm from Frank Wright to
> calculate the effective number of codons. Frank is a vegan (does not eat
> codfish), so in EMBOSS we renamed it "chips" :-)
>
> Hope that helps!
>
> Peter
>
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