I would kindly like to know whether it is possible to use two different testResults matrices from the same experiment (e.g. decideTests object from root and shoot) to create a venn diagram using limma vennDiagram() function? I know you might ask why? Because I can easily add the two tissues together and get the final results. However, I would like to analyse the tissues separately to see whether there is an effect of variance by having two tissues together in one statistical model (which would be like comparing a brain to a liver). As the final step of this I would like to see the overlap between the results I got for roots and shoots. Combining the matrices doesn't work because the number of genes are different in each object. I would therefore, kindly like to ask guidance from the experts in the field.