Distribution of transformed mean penalty scores by primer pair and genus. The sizes of the diamonds that represent the mean of the genera are proportional to the number of MOTUs in each genus. The overall mean value and standard deviations for each primer pair are shown in black. Means with a penalty above the red line (penalty score of 100) are considered in silico performance failures. The LCO1490/HCO2198 primer pair is indicated for reference purposes only, and not included in the statistical analysis.