Recently I had to annotate a large (10,000+) number of genes identified by Entrez Gene IDs. My goal was to avoid “annotation files” (basically CSV files) that a part of wet lab group likes, because I wanted to stay up-to-date without having to remember to update them. So the obvious solution was to use a service available on the web, and in an automated way. For reference, I just tried to attach gene symbol, gene name, chromosome and cytoband.

While working today on an annotation class in Python I stumbled on a problem. Normally I work with lists of genes that are consistent, i.e. all Entrez Gene IDs (or RefSeq IDs, or Genome Browser IDs…), but today I had a list of mixed identifiers. The subsequent idea was “let’s implement auto-detection of common identifiers in the class”. The problem is… is there any actual documentation on how identifiers are made?