(A) Shotgun sequencing of bulk fecal sample from three mice inoculated with WT Bt shows at least 2× coverage of the BT1871 locus.
(B) New Bt genomic junctions identified via shotgun sequencing of bulk fecal material from each mouse.
(C) Log-phase growth rates (k) of three mutant strains isolated from feces of mice colonized with WT Bt for 6 weeks compared to growth rate of the ancestral WT Bt in defined medium supplemented with melibiose (n = 4 technical replicates per strain). p < 0.05.
(D) Long-read MinION sequencing of an abundant mutant in mouse C (MZ65) reveals the duplication of a long segment including the BT1871 gene, which generates a tandem repeat of the locus. Each gray bar represents a single long read, which together span the region containing the tandem repeat.