Snail plots are based on the assembly-stats view used to convey several assembly metrics in a single graphic, originally used in LepBase. A red segment represents the longest scaffold while all other scaffolds are arranged in size-order moving clockwise around the plot and drawn in grey starting from the outside of the central plot. Dark and light orange arcs show the N50 and N90 values, which in this example are very small relative to the length of the longest scaffold. The central light grey spiral shows cumulative scaffold count with a white line at each order of magnitude. The dark vs. light blue area around the outside of the plot shows mean, maximum and minimum GC vs. AT content at 0.1% intervals. White regions in this area reflect the proportion of Ns in the assembly. If available, BUSCO scores are shown in the upper right-hand corner.

Command line

Generate a snail plot from a BlobDir using blobtools view.

1. Use an existing BlobDir, or create a minimal BlobDir using an assembly FASTA and BUSCO full table TSV file:

   blobtools create \
       --fasta /path/to/assembly.fasta \
       --busco /path/to/full_table.tsv \
       /path/to/BlobDir
   

2. Generate a snail plot:

   blobtools view \
       --plot \
       --view snail \
       /path/to/BlobDir