Dear users, Are all control probesets on affy chips suppose to be house-keeping (express to a certain extent?) The AFFX_rat_5s_rRNA probeset on my dataset (rat 230a arrays) seems to have extremely low intensity across all samples (around 1.3 after gcrma), I wonder if this is normal? Many thanks, Alex -------------------------------------------- Alex C. Lam Roslin Institute (Edinburgh) Midlothian EH25 9PS United Kingdom Tel: +44 131 5274471 Roslin Institute is a company limited by guarantee, registered in Scotland (registered number SC157100) and a Scottish Charity (registered number SC023592). Our registered office is at Roslin, Midlothian, EH25 9PS. VAT registration number 847380013. The information contained in this e-mail (including any attachments) is confidential and is intended for the use of the addressee only. The opinions expressed within this e-mail (including any attachments) are the opinions of the sender and do not necessarily constitute those of Roslin Institute (Edinburgh) ("the Institute") unless specifically stated by a sender who is duly authorised to do so on behalf of the Institute