Dear, It is convenient to use clusterprofiler in enrichment analysis. However, there is a problem confusing me in ID transformation.
I have a gene list containing 39570 genes with ensembl ID.
1. After transformation with bitr function from Ensembl to entrez ID, the number of genes is 22142, 44.39% of input gene IDs fail to map.
2. Transformation with bitr function from Ensembl to Symbol, the number of genes is also 22142, however, it contains duplicates. After removing duplicates, the number of genes is 22103.
I don't know why it happened. Any help will be greatly appreciated!
Thanks a lot.