Annotate gene list

[BM7]

I would like to annotate the results output file from Desq2 so it contains gene names and symbols. The RNA-seq count file I have used comes from Dexseq and contains ensembl gene IDs:
ENSMUSG00000000001:001
ENSMUSG00000000001:002
ENSMUSG00000000001:003
etc.
These refer to the the different exons of the gene.
I cannot annotate the result file because it contains the different exons. So how can I combine or merge the different exon counts for the same gene into one count for the gene?
Thanks in advance

[cmccabe]

I am not sure I understand completely, but if you have a file

ENSMUSG00000000001:001
ENSMUSG00000000001:002
ENSMUSG00000000001:003
ENSMUSG00000000002:001
ENSMUSG00000000002:002
ENSMUSG00000000002:002

you could use:

awk -F':' -v OFS='\t' '{sum[$1]+=$2} END{for (key in sum) print key, sum[key]}' file.txt
ENSMUSG00000000001      6
ENSMUSG00000000002      5

Hope this helps.