Gene loss within the SpyCI. The SpyCIM4 element is integrated within the MMR operon, between mutL and mutS (red arrows), and comprises 25 genes at full-length (as in MGAS10750) in the genomes of M4complete isolates. In the genomes of M4degraded isolates, including MEW427, the SpyCI element consists of only 11 genes, representing ~56 % gene loss. The pattern of degradation was common to all M4degraded. The SpyCI of BSAC_bs1802 is not shown, as this isolate contains a different SpyCI. Locus numbers for some genes are provided above and below; MEW427 is annotated in increments of five. The asterisks indicate an additional gene that was present but not included in the reference annotation. Colours represent predicted gene function according to the key.