mBin: a methylation-based binning framework for metagenomic SMRT sequencing reads
The mBin pipeline is designed to discover the unique signals of DNA methylation in metagenomic SMRT sequencing reads and leverage them for organism binning of assembled contigs or unassembled reads. Because all cellular DNA is modified by the same set of methyltransferases encoded in the genome, DNA methylation signals can be used for binning not just chromosomal sequences, but also extrachromosomal mobile genetic elements like plasmids.
The pipeline consists of four routines:
- buildcontrols: Gets unmethylated IPD values for motifs from whole-genome amplified (WGA) sequencing
- filtermotifs: Identifies methylated motifs in native metagenomic sequencing
- methylprofiles: Creates methylation profiles for sequences using specified motifs
- mapfeatures: Visualizes landscape of methylation features across all sequences
mBin can take as input either unaligned single molecule real-time (SMRT) reads from a PacBio instrument or contigs assembled from SMRT reads. Methylation scores are calculated from individual inter-pulse duration (IPD) metrics embedded in each sequencing read that record the polymerase kinetics during sequencing and indicate the presence or absence of DNA methylation at the level of individual nucleotides.
By aggregating these IPD metrics across multiple sites for a motif and across multiple reads aligned to a contig, mBin generates methylation scores for motifs and uses these to construct methylation profiles for reads and contigs. Methylation profiles can then be used as epigenetic features for unsupervised metagenomic binning. mBin can also generate methylation scores for contigs that are given binning assignments by other binning tools (with the –cross_cov_bins option).
For a comprehensive guide on how to install mBin and its dependencies, see Installation
- mBin overview