How to create a customized OrgDb in order to perform kegga analysis?
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baus87 • 0
@baus87-13757
Last seen 3.2 years ago

Hi,

i'm working on a set of DEGs and i'd like to analyze them using the kegga function. Since i'm working on a species whose OrgDb is not implemented in, how can i create an in-house dedicated OrgDb?

Antonio

limma kegga orgdb • 600 views
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@gordon-smyth
Last seen 53 minutes ago
WEHI, Melbourne, Australia

You don't need an OrgDb package to run kegga(). kegga simply reads annotation from the KEGG website.

However KEGG does not provide annotation for the Trichoderma gamsii species, as you can see from their website:

http://www.kegg.jp/kegg/catalog/org_list.html

The closest species is Trichoderma reesei.

So you can't do a KEGG enrichment analysis for Trichoderma gamsii because KEGG pathways don't exist for that species.

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Dear Gordon,
i'm working with Trichoderma gamsii (filamentous fungus). I'd like to perform a kegg enrichment analysis upon DEGs. Is it kegga suitable for this purpose?

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Ok, got it.
Could you recommend me any alternative tool?

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Let me ask you in turn: is there any pathway / annotation info publicly available for this organism? At KEGG apparently not... Being a person working with T gamsii I suppose you should know this.... If there isn't, you cannot expect members of this (Bioconductor) support site to give you a useful answer to your last question....

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Dear Guido,
nowadays i'm annotating my reference genomes with ko codes from KEGG. Given a set o differentially expressed genes, I was just looking for the proper enrichment analysis to be applied. Maybe my first post has been misleading, sorry for that.
Antonio

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Aha, AFAIK in that case you can use the argument species.KEGG = "ko" when using the function kegga().

Assuming DEGs is a character vector with the differentially expressed KO IDs, something like:

k<- kegga(DEGs, species.KEGG = "ko", FDR = 0.05)