Dear members, I am seeking for an efficient way to sort the genes into different categories. I am working on the analysis of the microarray data and now I encounter a problem. After getting the differentially expressed genes, I want to sort them into different categories according to their functions. However, I find it hard to set up a criteria to classify them. Now I am trying to employ the KEGG Orthology to facilitate the sortation, but the genes without the KO entries become homeless. I wonder how you sort the genes. Furthermore, if anyone has used the GO Slim to classify the genes, please give a comment on it. Thank you.