To further explore the effect of the adaptive immune system of NOD and 116C-NOD models on their gut microbiota, faecal samples from the immunodeficient variants NOD.RAG-2−/− and 116C-NOD.RAG-2−/−, as well as from a non-T1D-prone mouse control, were also analysed. This evidence concerns the gene RAG2 and type 1 diabetes mellitus.