I'd like to annotate a DESeqDataSet with information on gene size, specifically populating mcols(dds)$basepairs, where dds is my DESeqDataSet. The DESeqDataSet was created from HTSeq output, using the DESeqDataSetFromHTSeqCount function.
The reason for this is to pull out FPKMs, and to have genomic intervals for other downstream analysis. The HTSeq counts are by gene symbol.
Genome in this case is hg19, and I have TxDb.Hsapiens.UCSC.hg19.knownGene and Org.Hs.eg.db data, but not sure which slots to match.
Any suggestions would be really appreciated. thanks!