Sorry, Yang. The GTF file that I used wasn't the one I shared, but it is the NCBI one (GCF_000001405.39_GRCh38.p13_genomic.gtf). I had a look at this file and yes, the gene_id is the gene symbol.
If I may add some details to what my issue actually is:
My index was built using NCBI 's GRCh38_latest_genomic.fna.
For the counts, I used the NCBI gtf file mentioned above.
The first time I ran my data, the output read-count table listed down as Ensemble_gene_ids
MR1.bam MR2.bam MR3.bam MR4.bam MR5.bam MR6.bam MR7.bam MR8.bam MR9.bam MR10.bam MR11.bam MR12.bam MR13.bam MR14.bam MR15.bam MR16.bam MR17.bam MR18.bam MR19.bam MR20.bam
ENSG00000223972 3 5 7 8 5 2 6 2 2 3 0 4 2 1 3 3 5 1 4 0
ENSG00000227232 148 249 188 162 185 188 205 144 144 238 97 184 222 157 175 177 132 176 134 136
ENSG00000278267 9 9 5 8 8 11 14 3 7 25 8 11 5 10 13 6 6 17 3 6
ENSG00000243485 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0
When I ran another set of data in a different setting but using the exact same index and gtf file, I seem to be getting gene symbols.
"A096CD.bam" "A096SGN.bam" "A096VD.bam" "A096VGN.bam" "A204NB.bam" "A204OV.bam" "A205CD.bam" "A205SGN.bam" "A205VD.bam" "A205VGN.bam" "A211NB.bam" "A211OV.bam" "A216NB.bam" "A216OV.bam" "A218CD.bam" "A218SGN.bam" "A218VD.bam" "A218VGN.bam" "A220CD.bam" "A220SGN.bam" "A220VD.bam" "A220VGN.bam" "A226NB.bam" "A226OV.bam" "A228CD.bam" "A228SGN.bam" "A228VD.bam" "A228VGN.bam" "A237CD.bam" "A237SGN.bam" "A237VD.bam" "A237VGN.bam" "A240CD.bam" "A240SGN.bam" "A240VD.bam" "A240VGN.bam" "A242CD.bam" "A242SGN.bam" "A242VD.bam" "A242VGN.bam" "A245CD.bam" "A245SGN.bam" "A245VD.bam" "A245VGN.bam" "A247CD.bam" "A247SGN.bam" "A247VD.bam" "A247VGN.bam"
"DDX11L1" 0 0 0 3 0 0 3 0 0 0 0 0 0 0 0 0 3 1 2 0 0 1 0 0 0 0 0 1 1 0 1 1 0 0 0 0 0 2 0 0 0 0 1 0 0 0 0 0
"WASH7P" 75 93 135 56 104 72 159 86 183 122 70 107 16 67 88 42 59 51 79 37 73 54 133 116 193 145 102 102 235 125 263 187 126 101 122 82 115 51 96 101 190 79 66 100 166 107 97 149
"MIR6859-1" 0 0 0 0 0 0 2 0 1 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 1 0 0 0 8 2 0 0
"MIR1302-2HG" 0 3 5 5 0 3 0 2 2 1 3 1 0 0 0 0 3 1 3 2 4 2 2 0 2 1 1 1 4 3 0 1 4 0 0 0 0 1 2 0 2 3 4 0 3 1 12 1
I am quite confident that I didn't change anything to my codes or to the gtf file, so I am a bit confused as to why the difference in the output reads and thought perhaps there was some update to the package that I would now need specify when I run the featureCounts.
Many thanks.