For a shotgun metagenomic study I want to perform the differential abundance analysis (taxa and function) comparing 4 groups: please, can you confirm that, once I got a gene abundance table, I will be able to run a two factor analysis (a two way ANOVA) for both taxa and function using your tool?
No, we do not support two-way ANOVA in MicrobiomeAnalyst. However, there is a multi-factor regression tool that will allow you to incorporate any number of experimental factors. Please see the tutorials and explore the tool on your own.