Illumina annotation packages for version 1 of the mouse and human Sentrix beadchips are now available in the bioconductor 2.0 repository. http://www.bioconductor.org/packages/2.0/IlluminaChip.html These can be used for either the WholeGenome or RefSeq8 chips. The probe ID is the Target ID provided by Illumina. Accession IDs were taken from http://www.illumina.com/General/Products/ArraysReagents/zip_files /Human_WG-6_rev.zip and http://www.illumina.com/General/products/arraysreagents/Excel/Mouse6_G ene_List.xls Let me know if you have any problems or questions. Lynn Amon