mcorr-clustering

This repository contains everything needed to do hierarchical clustering using mcorr. It takes in gap-filtered XMFA files generated from our ReferenceAlignmentGenerator, clusters them using average linkage (UPGMA) using synonymous diversity as the distance metric and outputs pairwise distances, a sequence tree, and XMFA files for the core and accessory genes of each sequence cluster.

Installation

For basic usage (hierarchical clustering of a small dataset ~100-5000 whole genome sequences) clone this repository and install the program clusterWrite via pip:

pip install ~/go/src/github.com/kussell-lab/mcorr-clustering/clusterWriteXMFA

you need to then install the following in-house developed programs found in this repo:

• go get -u github.com/kussell-lab/mcorr-clustering/mcorr-pair
• go get -u github.com/kussell-lab/mcorr-clustering/mcorr-dm
• go get -u github.com/kussell-lab/mcorr-clustering/ClusterSplit

For doing hierarchical clustering of large datasets ~20,000 whole genome sequences, you can install all the CLI programs needed from this repo via the go get command, with the exception of the program clusterSequences, which can also be installed via pip:

pip install ~/go/src/github.com/kussell-lab/mcorr-clustering/clusterSequences

Usage

Small datasets (<5,000 sequences)

Datasets with <5000 sequences can be run in several hours using clusterWrite. You can input clusterWrite --help into your terminal to see the inputs. This makes flat clusters based on the pairwise distance between sequences, and you can change the cutoff percentile (which is the percentile of all the distances) at which the tree is cut. You can also change the minimum number of strains for a cluster to be included.

large datasets (~20,000 sequences)

For large datasets, you can cluster these sequences in several steps:

(1) Use ChunkMSA to divide up your XMFA file into several chunks

(2) Use mcorr-pair-sync to measure a subset of all of the pairwise distances necessary for the final distance matrix. Here, you can run these jobs in parallel on an HPC to speed up the process.

(3) Once your parallelized jobs are completed, you can collect the results into a single distance matrix using mcorr-dm-chunks.

(4) You can then run clusterSequences to cluster the sequences and ClusterSplit to split up the original XMFA into XMFA files for each sequence cluster.

Examples

See the subdirectory "hinfluenzae_example" to run both of the described examples.

clusterWrite example

For an example of how to run clusterWrite, run the clusterWrite_example.sh script. This should only take a few seconds to run on a standard PC.

Example using mcorr-pair-sync

If you're interested in clustering and writing XMFA files for collections of 10,000 to 30,000 sequences, you can parallelize mcorr-pair-sync over an HPC. An example workflow is given in the script mcorrpairsync_example.sh. Step 2 is what would be run as parallel jobs on an HPC.