Obtain peptide sequences for a manageable sampling of prokaryotic genomes for small-scale comparative genomics and/or phylogenetics analyses.
Inclusive databases such as the NCBI nr database contain data for so many prokaryotic genomes, that obtaining sequences from a representative sampling of bacteria or archaea via NCBI's Basic Local Alignment Search Tool (BLAST) or other means becomes difficult without restricting searches to a relatively small selection of genomes. However, selected genomes must be representative for the taxonomic scope of interest, being relatively complete and high quality, otherwise comparative genomics results will be compromised.
Zhu et al. describe a systematic selection of representative prokaryotic genomes in this article:
Zhu, Q., Mai, U., Pfeiffer, W., Janssen, S., Asnicar, F., Sanders, J.G.,
Belda-Ferre, P., Al-Ghalith, G.A., Kopylova, E., McDonald, D., Kosciolek,
T., Yin, J.B., Huang, S., Salam, N., Jiao, J.-Y., Wu, Z., Xu, Z.Z.,
Cantrell, K., Yang, Y., Sayyari, E., Rabiee, M., Morton, J.T., Podell, S.,
Knights, D., Li, W.-J., Huttenhower, C., Segata, N., Smarr, L., Mirarab,
S., Knight, R., 2019. Phylogenomics of 10,575 genomes reveals evolutionary
proximity between domains Bacteria and Archaea. Nat Commun 10, 5477.
https://doi.org/10.1038/s41467-019-13443-4
They provide a data sheet of information about each of the genomes they selected, including taxonomic information and information on assembly quality, etc. here:
https://biocore.github.io/wol/data/genomes/metadata.tsv.bz2
They describe how to retrieve their genome and protein data here (you have to use Globus):
https://biocore.github.io/wol/data/genomes/
For smaller-scale comparative genomics studies, it will be necessary to obtain a subsampling of these 10,575 representative genomes in a systematic manner according to measures of quality and taxonomic diversity. That is what this script does.
- Linux or MacOS operating system
- Python3
- The pandas python library
- Git
- bzip2
-
Obtain the
per_genome.tarfile containing peptide sequence FASTA files from here via Globus: https://app.globus.org/file-manager?origin_id=31acbeb8-c62f-11ea-bef9-0e716405a293&origin_path=%2Fproteins%2F -
Decompress the tar file.
-
Clone this repository.
git clone https://github.com/laelbarlow/wol_peptide_subsampler.git -
Change directories into the repository.
cd wol_peptide_subsampler -
Subsample the protein sequence files according to measures of quality and taxonomic diversity (as detailed in the TSV file).
python3 subsample_wol_peptides.py <path to per_genome dir> -
Examine the CSV file with information for only the subsampled genomes here:
results/metadata_subsample.csv -
Proceed with downstream analysis of the selected peptide FASTA files here:
results/peptide_seqs_subsample/
MIT License
Copyright (c) 2020 Lael D. Barlow
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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