The gene for a cell surface-localized haemolysin-like protein, HlyA (sll1951), reported to function as a barrier against the adsorption of toxic compounds,25,26 is lacking one nucleotide in ‘PCC-M’ compared with the reference (difference #15). In the ‘GT-Kazusa’, ‘GT-V’ as well as the ‘GT-I’ and ‘GT-S’ strains,9 the presence of the additional A leads to the fusion of two ORFs that are separate in ‘PCC-M’, ‘PCC-N’ and ‘PCC-P’ substrains.9 As a result, Sll1951 is 1741 amino acids in the former and only 1437 residues in the latter.