Correlations of the biovolumes of the toxic genotype and two lineages differing in pigmentation with the total biovolume of Planktothrix. Relationship between the mean ± SE biovolume of Planktothrix as determined by 16S rDNA, the mcy-containing genotype and two clonal complexes of Planktothrix: lineage 1 (green-pigmented strains that lost the mcy gene cluster) and lineage 2 (red- or green-pigmented strains that always contain the mcy gene cluster). Biovolume in mm3 L-1. Details on the regression curves are given in the text. PSA-IGS: P700 apoprotein subunit Ia and Ib intergenic spacer.