Hi all,

I'm trying to find the names (e.g. SYMBOLS) corresponding to gene ID using the "org.Dm.eg.db" and "TxDb.Dmelanogaster.UCSC.dm3.ensGene" libraries. I have done it (and it works) when I try with the mm9 (mouse) genome, but some how, I get an error if I try with the drosophila genome.

I have pasted some code below:

Part1: Mouse genome and libraries. This works  with no error.

Part2: Drosophila genome and librairies. I get the following error:

 Error in .testForValidKeys(x, keys, keytype) : 
  None of the keys entered are valid keys for 'ENTREZID'. Please use the keys method to see a listing of valid arguments.

However, when I try to look at the possible keys, the "SYMBOL" is present, so I don't understand..

 keytypes(drosoDB2)
 [1] "ENTREZID"     "ACCNUM"       "ALIAS"        "CHR"          "CHRLOC"      
 [6] "CHRLOCEND"    "ENZYME"       "MAP"          "PATH"         "PMID"        
[11] "REFSEQ"       "SYMBOL"       "UNIGENE"      "ENSEMBL"      "ENSEMBLPROT" 
[16] "ENSEMBLTRANS" "GENENAME"     "UNIPROT"      "GO"           "EVIDENCE"    
[21] "ONTOLOGY"     "GOALL"        "EVIDENCEALL"  "ONTOLOGYALL"  "FLYBASE"     
[26] "FLYBASECG"    "FLYBASEPROT" 

Any help would be greatly appreciated. Thanks!

Part 1 (Mouse)

   TaxonDatabaseKG <- "TxDb.Mmusculus.UCSC.mm9.knownGene"
   TaxonDatabaseDict <- "org.Mm.eg.db"
   library(TaxonDatabaseKG, character.only = TRUE)
   library(TaxonDatabaseDict, character.only = TRUE)
   exonRanges <- exonsBy(get(TaxonDatabaseKG), by = "gene")
   symb <- select(get(TaxonDatabaseDict), names(exonRanges), columns = "SYMBOL")
   mouseDB1 <- get("TxDb.Mmusculus.UCSC.mm9.knownGene")
   keytypes(mouseDB1)
   help('select')
   mouseDB2 <- get("org.Mm.eg.db")
   keytypes(mouseDB)
   symb <- select(get(TaxonDatabaseDict), names(exonRanges), columns = "SYMBOL")

Part 2 (Drosophila)

  
   TaxonDatabaseKG <- "TxDb.Dmelanogaster.UCSC.dm3.ensGene"
   TaxonDatabaseDict <- "org.Dm.eg.db"
   library(TaxonDatabaseKG, character.only = TRUE)
   library(TaxonDatabaseDict, character.only = TRUE)
   exonRanges <- exonsBy(get(TaxonDatabaseKG), by = "gene")
   symb <- select(get(TaxonDatabaseDict), names(exonRanges), columns = "SYMBOL")
   drosoDB1 <- get("TxDb.Dmelanogaster.UCSC.dm3.ensGene")
   keytypes(drosoDB1)
   drosoDB2 <- get("org.Dm.eg.db")
   keytypes(drosoDB2)
   symb <- select(get(TaxonDatabaseDict), names(exonRanges), columns = "SYMBOL")
  

Note the error you got:

Error in .testForValidKeys(x, keys, keytype) : 
  None of the keys entered are valid keys for 'ENTREZID'. Please use the keys method to see a listing of valid arguments.

That's intended to be pretty clear - the keys you are using are (by default) expected to be Entrez Gene IDs, but what you are passing in do not appear to be Entrez Gene IDs. So let's look at what we have here:

> exonRanges <- exonsBy(TxDb.Dmelanogaster.UCSC.dm3.ensGene, by = "gene")
> head(names(exonRanges))
[1] "FBgn0000003" "FBgn0000008" "FBgn0000014" "FBgn0000015" "FBgn0000017"
[6] "FBgn0000018"

So that makes sense - those look like flybase IDs to me, not Entrez Gene IDs.

> select(org.Dm.eg.db, head(names(exonRanges)), "SYMBOL","FLYBASE")
      FLYBASE         SYMBOL
1 FBgn0000003 7SLRNA:CR32864
2 FBgn0000008              a
3 FBgn0000014          abd-A
4 FBgn0000015          Abd-B
5 FBgn0000017            Abl
6 FBgn0000018            abo

Great, thanks a lot!