How To Get Flybase Gene Id According To Kegg Gene Id?
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10.6 years ago
Dejian ★ 1.3k

I got a list of kegg gene ID for fruitfly. Now I want to get these sequences. I think mapping these KEGG gene ID to flybase gene ID and then extracting the sequences from flybase is a good way to do the job. I am sure there is a map between kegg gene id and flybase gene id (see below), however, I do not know where it is. Give me a hint? Thanks!

Dmel_CG10219 <> FBgn0039112

Dmel_CG10320 <> FBgn0034645

kegg identifiers • 4.2k views
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10.6 years ago

The CG identifiers are not Kegg gene ids but the FlyBase Computed Gene IDs. The CG id nomeclature was inherited from Celera/Berkeley and then gene model names were rationalized into the FlyBase paradigm, where all object types are given a FBxx id, where FB=FlyBase and xx=object type (in this case, gene name).

To get a mapping between CGids <-> FBgns, use biomart, with this query.

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Thanks, Casey. The query you provided is right what I want.

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10.6 years ago

If you have KEGG gene IDs, and you want to get the sequences, why not simply download the sequences from KEGG and save yourself the painful and error-prone mapping exercise?

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You are right. This is the most convenient way to do my current job. Many thanks, Lars.

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10.6 years ago
Joachim ★ 2.9k

You are accessing the FlyBase database directly, right?

CG10219 and CG10320 are synonyms in FlyBase, which you can use to get the FlyBase gene ID as follows:

SELECT DISTINCT
f.uniquename
FROM
feature f,
synonym s,
feature_synonym fs
WHERE
s.name = 'CG10219'
AND
s.synonym_id = fs.synonym_id
AND
f.feature_id = fs.feature_id
AND
f.organism_id = 1;;


Some explanation:

• You need DISTINCT because there are several mappings in feature_synonym that match the same synonym_id and feature_id, but differ in pub_id (otherwise it will just return the FlyBase ID a couple of times)
• You need to match organism_id because otherwise you get non-dmel results too
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No. I am trying to download a batch of sequences from the website of FlyBase. The batch download accepts IDs like CG.However, a CG-like ID ofen corresponds to more than one FBgn ID and only one of them is what I want. Thus, it is inconvenient to use the batch download on the website. Any other method? Thanks.