I am looking for an efficient way of retrieving the upstream flanking regions of a specific gene which is present in many bacterial species. The homologs share the same name, so that should be easy. I tried using Biomart (which I have practically no experience with) but there it seems I can only retrieve sequences from one database/species at a time.
When I search for the gene name in NCBI I get all results that I want but I don't know how to automatize retrieving the upstream regions.
Thank you.