Fig. 3

Unique k-mer count separates true and false positives better than read counts in a complex dataset with ten million reads sampled from SRA experiments. Each dot represents a species, with true species in orange and false species in black. The dashed and dotted lines show the k-mer thresholds for the ideal F1 score and recall at a maximum of 5% FDR, respectively. In this dataset, a unique k-mer count in the range 10,000–20,000 would give the best threshold for selecting true species