Figure 3

Plots from of k-mer profiling. a) K-mer frequency histogram of E.coli MiSeq dataset shows an obvious peak k-mer coverage near 216X (small arrow, inset figure) and a minimum inflection point at ~41X (long arrow, inset figure). The k-mers below than the minimum inflection point are due to sequencing artifacts and errors. The other small peaks typically indicate repeats in the genome. b) K-mer rarefaction curve shows a reduction of k-mers when trimming. The blue and red soild lines are the k-mer rarefaction curves of raw and trimmed E.coli MiSeq data, respectively. The green and beige solid lines are k-mer rarefaction curves of raw and trimmed data of the HMP Mock data, respectively. The dashed line represents the baseline where all observed k-mers are distinct.