Abstract

MotivationTracking disease outbreaks by whole-genome sequencing leads to the collection of large samples of closely related sequences. Five years ago, we published a method to accurately compute all pairwise distances for such samples by indexing each sequence. Since indexing is slow, we now ask whether it is possible to achieve similar accuracy when indexing only a single sequence.ResultsWe have implemented this idea in the program phylonium and show that it is as accurate as its predecessor and roughly 100 times faster when applied to all 2678 Escherichia coli genomes contained in ENSEMBL. One of the best published programs for rapidly computing pairwise distances, mash, analyzes the same dataset four times faster but, with default settings, it is less accurate than phylonium.Availability and implementation Phylonium runs under the UNIX command line; its C++ sources and documentation are available from github.com/evolbioinf/phylonium.Supplementary information Supplementary data are available at Bioinformatics online.

Highlights

  • Methods for rapid sequence comparison are a staple of bioinformatics, if not its raison d’etre

  • We ask whether it is possible to achieve similar accuracy when indexing only a single sequence. We have implemented this idea in the program phylonium and show that it is as accurate as its predecessor and roughly 100 times faster when applied to all 2678 Escherichia coli genomes contained in ENSEMBL

  • The tree of 29 Escherichia coli/Shigella genomes with an average length of 4.9 Mb in Figure 2A is based on a mugsy alignment computed in 2 h 18 min

Read more

Summary

Introduction

Methods for rapid sequence comparison are a staple of bioinformatics, if not its raison d’etre. Genome aligners like mugsy have allowed the comparison of whole genome samples (Angiuoli and Salzberg, 2011). The tree of 29 Escherichia coli/Shigella genomes with an average length of 4.9 Mb in Figure 2A is based on a mugsy alignment computed in 2 h 18 min. This large run time illustrates that genome aligners like mugsy do not scale well with sample size. Distance matrices can be computed from genomes without first explicitly aligning all residues, leading to much faster methods of phylogeny reconstruction

Objectives
Methods
Results
Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call