I am a cookie in RNA-Seq analysis so I am really confused with the Ensembl id and gene symbol. I have checked some associated posts in Biostars but I didn't find what I want eventually. The problem is that I noticed one Ensembl id matches multiple gene symbols, but I do not know how to deal with this issue when I want to do some analysis based on gene symbols. Should I add the counts of the same symbol together? Thanks in advance for the reply!