Fig. 2

Assembly graphs become more complex as coverage increases. MEGAHIT assembly graphs (k = 41) of an E. coli K12 genome for 2 ×, 32 ×, and 512 × per-base coverage, respectively, visualized with Bandage [60]. For 2 × coverage, the graph is disconnected and thus the assembly fragmented. With increasing coverage more and more unitigs can be joined, first resulting in a decent assembly for 32 × coverage, but—due to sequencing errors adding erroneous edges to the graph—a fragmented assembly again for 512 × coverage