I've been researching but haven't found any result yet. Do you think there is some (statistical) methods designed for detecting Differentially Expressed Genes among different tissues in an organism during time? I mean do you think it is possible to find out what genes are expressed differentially in different tissues in time series RNA-seq data? It is like a factorial design (study) in which we have "time" and "different tissues" as possible factors that may influence expression of genes. If there is no direct method to do so, what do you recommend to solve such problems?