SqueezeM, a highly portable, fully automatic metagenomic analysis pipeline

Abstract

The improvement of sequencing technologies has allowed the generalization of metagenomic sequencing, which has become a standard procedure for analysing the structure and functionality of microbiomes. The bioinformatic analysis of the sequencing results poses a challenge because it involves many different complex steps. SqueezeMeta is a full automatic pipeline for metagenomics/metatranscriptomics, covering all steps of the analysis. SqueezeMeta includes multi-metagenome support allowing the co-assembly of related metagenomes and the retrieval of individual genomes via binning procedures. SqueezeMeta features several unique characteristics: Co-assembly procedure or co-assembly of unlimited number of metagenomes via merging of individual assembled metagenomes, both with read mapping for estimation of the abundances of genes in each metagenome. It also includes binning and bin checking for retrieving individual genomes. Internal checks for the assembly and binning steps inform about the consistency of contigs and bins. Also, the results are stored in a mySQL database, where they can be easily exported and shared, and can be inspected anywhere using a flexible web interface allowing the easy creation of complex queries.\n\nWe illustrate the potential of SqueezeMeta by analyzing 32 gut metagenomes in a fully automatic way, allowing to retrieve several millions of genes and several hundreds of genomic bins.\n\nOne of the motivations in the development of SqueezeMeta was producing a software capable to run in small desktop computers, thus being amenable to all users and all settings. We were also able to co-assemble two of these metagenomes and complete the full analysis in less than one day using a simple laptop computer, illustrating the capacity of SqueezeMeta to run without high-performance computing infrastructure. SqueezeMeta is a complete system covering all steps in the analysis of metagenomes and metatranscriptomes, capable to work even in scarcity of computational resources. It is therefore adequate for in-situ, real time analysis of metagenomes produced by nanopore sequencing.\n\nSqueezeMeta can be downloaded from https://github.com/jtamames/SqueezeMeta