Pandora: nucleotide-resolution bacterial pan-genomics with reference graphs.
Colquhoun RM., Hall MB., Lima L., Roberts LW., Malone KM., Hunt M., Letcher B., Hawkey J., George S., Pankhurst L., Iqbal Z.
We present pandora, a novel pan-genome graph structure and algorithms for identifying variants across the full bacterial pan-genome. As much bacterial adaptability hinges on the accessory genome, methods which analyze SNPs in just the core genome have unsatisfactory limitations. Pandora approximates a sequenced genome as a recombinant of references, detects novel variation and pan-genotypes multiple samples. Using a reference graph of 578 Escherichia coli genomes, we compare 20 diverse isolates. Pandora recovers more rare SNPs than single-reference-based tools, is significantly better than picking the closest RefSeq reference, and provides a stable framework for analyzing diverse samples without reference bias.