design: Bacteria from murine fecal samples were sorted based on bound IgA or left unsorted to obtain three populations (unsorted-whole, IgA-positive, and IgA-negative). DNA was extracted and the V4 region of the 16S rDNA gene was amplified using PCR with the Schloss SOP. These amplicons were dual-indexed and read on an Illumina MiSeq with a paired-end 500 cycle kit (2x250bp reads).