We have recently updated the HOMOLOGS section of our symbol reports to show multiple mouse and rat homologs for each human gene, where applicable. This also means that there will be multiple MGI or RGD IDs within the download files, which are comma space (ie ‘, ‘) separated within the tab separated output. The REST API output has also changed for RGD and MGD data as they are now within an array named mgd_id and rgd_id (see REST web-service help).