Potential and pitfalls of eukaryotic metagenome skimming: A test case for lichens

Whole genome shotgun sequencing of multi species communities using only a single library layout is commonly used to assess taxonomic and functional diversity of microbial assemblages. Here we investigate to what extent such metagenome skimming approaches are applicable for in-depth genomic characterizations of eukaryotic communities, e.g. lichens. We address how to best assemble a particular eukaryotic metagenome skimming data, what pitfalls can occur, and what genome quality can be expected from this data. To facilitate a project specific benchmarking, we introduce the concept of twin sets, simulated data resembling the outcome of a particular metagenome sequencing study. We show that the quality of genome reconstructions depends essentially on assembler choice. Individual tools, including the metagenome assemblers Omega and MetaVelvet, are surprisingly sensitive to low and uneven coverages. In combination with the routine of assembly parameter choice to optimize the assembly N50 size,...