Does anyone notice that the number of records (~7000 unique gene ids) from table "ensembl_prot" extracted from extdata/org.Hs.eg.sqlite in source package org.Hs.eg.db_3.4.0.tar.gz does not match the number of unique genes (~20,000) from R script as following:

--

// Get the entrez gene IDs that are mapped to an Ensembl ID

x <- org.Hs.egENSEMBLPROT

mapped_genes <- mappedkeys(x)

// Convert to a list

xx <- as.list(x[mapped_genes])

--

xx has a length of ~20,000

I don't know what is going wrong?