Toll-like receptor (TLR) signaling has been implicated in the regulation of intestinal microbiota. In the Journal of Experimental Medicine, Pamer and colleagues use high-throughput sequencing of 16S rRNA genes from the small and large intestines of mice to assess the contribution of TLR-deficiency versus maternal transmission on the composition of intestinal microbiota. Comparison of TLR-deficient and wild-type littermates that were housed together indicates that deficiency in TLR2, TLR4, TLR5, TLR9 and the adaptor MyD88 does not result in significant changes in the composition, richness or diversity of intestinal microbiota under homeostatic conditions or after recovery from antibiotic treatment. The authors report marked differences between wild-type and TLR-deficient colonies that were bred in isolation of each other for long periods. These results suggest maternal origin is the major factor driving microbiota diversity.

J. Exp. Med. (23 July 2012) doi:10.1084/jem.20120504