Figure 6. Highly contiguous assemblies can be obtained with lower coverage of ultra-long reads.

The NGx curve is shown for Drosophila jambulina assemblies at varying levels of coverage. The length of the assembly with the full data is assumed to be the genome size. Read sets used for each assembly were obtained by randomly downsampling the basecalled reads (read N50 ~27.5 kb) to varying (5× to 30×) depth of coverage. Proportionally, these read sets contain ~55% of total sequenced bases in reads longer than 25 kb, ~25% of bases in reads longer than 50 kb, and ~7% of bases in reads longer than 100 kb. Near chromosome scale assemblies (N50>20Mb) were achievable even at 15× to 20× depth with this read length distribution. This corresponds to approximately 8× to 10× depth in reads longer than 25 kb.