If you are looking for the reference that was specified in your bam file and can find it in: http://www.bcgsc.ca/downloads/genomes/ We apologize in advance. Please contact the BioApplications Team at bioapps@bcgsc.ca with the subject line: "Missing in http://www.bcgsc.ca/downloads/genomes/" where is the species that is absent from the downloads directory. i.e. "Missing Saccharomyces_cerevisiae in http://www.bcgsc.ca/downloads/genomes/" We will upload the reference and email you as soon as it is available. Thank you.