In bio-breeding rats, a difference in microbiota composition was seen prior to onset of T1D in animals that are prone to the disease versus ones that are protected10, and a transferable protection has also been observed in non-obese diabetic mice lacking MyD88 (myeloid differentiation primary response gene 88), an essential signal transducer in Toll-like receptor signaling11,12. Here, MYD88 is linked to type 1 diabetes mellitus.