Initial studies characterising the PGM reported that there was little correlation between genomic coverage and G+C% content. More recently it was claimed that, based on visual comparisons of the theoretical versus empirical genomic coverage, there was substantially less read coverage in A+T rich regions [3]. Here, we attempt to quantify the magnitude and significance of the relationship between coverage and G+C content. Inspection of the data suggested that the relationship between G+C% and coverage differs for the two species used in this study ( Figure 1a ). While B. amyloliquefaciens has a higher mean G+C (46.1%) compared to S. tokodaii (32.8%), both have a large number of 100 bp windows within the range of 20–50% G+C content, allowing direct comparison ( Figure 1b ). The positive correlation between G+C and coverage in S. tokodaii versus the negative correlation with B. amyloliquefaciens is clear even when restricting to this 20–50% G+C range. This suggests that the relationship between G+C% and coverage is influenced by the DNA template from which the sequences are derived. We fitted a linear model to the normalised
