Hi! I am a beginner in Bioinformatics and have a BioMart question. I have microarray Affy-id:s from Affymetrix Mouse Genome 430 2.0 Array and want the corresponding ENSG-ids from BioMart. The Array has 45 101 Affy-id:s, but I only get 33 750 corresponding ENSG-id:s in BioMart. Can I expect a 1:1 correspondence, or have I used BioMart in the wrong way? As I have understand it reading articles and other questions in the forum about the subject, there may be fewer corresponding ENSG-id:s to the probes?
Also, the microarray experiment I´m analysing is from GEO and was done (submitted) 2007. In this, I already have the corresponding gene names for each probe at the time. Can the probe id corresponding to certain gene(s) have changed or can I trust that the gene - names are the same for the probes today?