Hello, I am currently working on a rather strange project where amoeba along with a human cell line have been hybridised to an Agilent 4x44k microarray. As I wouldn't expect the majority of probes for the amoeba sample to be expressed, the assumption for LOESS that on average there isn't any difference between samples does not hold. So as an alternative I have considered normalising LOESS but only using the Agilent control probes. Is this reasonable? or is there a better approach? Also does anyone know what all the types of control probes on the Agilent array are? Many thanks Dan -- ************************************************************** Daniel Brewer, Ph.D. Institute of Cancer Research Molecular Carcinogenesis Email: daniel.brewer at icr.ac.uk ************************************************************** The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the a...{{dropped:2}}