Dear Prof Smith, dear Bioconductor's user, I am using Limma to analyse time series microarray gene expression data. I have 4 time points (t1: 40 RNAs, t2:42, t3:20,t4:30). RNAs are isolated from 42 patients. could you tell me how can I set the design matrix, there is no replicates and it is only one condition which is compared over time (i.e there is no treatment factor). Thank you for your help, Claire P [[alternative HTML version deleted]]