FIG 1.

Metagenomic read mapping suggests three distinct mcy genotypes in western Lake Erie Microcystis populations at different times and locations. Genotypes were inferred by mapping metagenomic reads onto the reference mcy operon from Microcystis aeruginosa reference strain PCC 7806 (GenBank accession number AF183408.1). For each plot, the top panel indicates the percent identity of the read mapped to the reference operon, and the bottom panel shows coverage (number of reads mapped per position). The color of the genes indicates modular enzymes encoded by mcy genes. (A) Mapping results from a sample dominated by the complete genotype (WE12, 4 August). The asterisks indicate evidence of recombination in which the C1 domain replaced the B1 domain, creating a C1-like mcyB genotype, which is interpreted to dominate the metagenome of this sample (bottom operon). The lack of this recombination preserves the mcyB orientation for a B1-like mcyB genotype (top operon), as in the reference sequence from PCC 7806. (B) Sample dominated by the partial genotype (WE12, 23 September). (C) Absent genotype with no mcy genes present.