S. pyogenes M1global genotype strains 5448 (invasive disease; ssa−, speC−, spd1−, speA+)25, HKU488 (scarlet fever; ssa+, speC+, spd1+, speA+)24 and an Australian S. pyogenes M1global clinical isolate SP1426 (scarlet fever; ssa-, speC+, spd1+, speA+) were used as benchmark reference strains for comparison with Australian M1UK strains (Fig. 1b and Supplementary Fig. 2). Here, HOXD13 is linked to scarlet fever.