Learning Microbial Interaction Networks from Metagenomic Count Data.
Many microbes associate with higher eukaryotes and impact their vitality. To engineer microbiomes for host benefit, we must understand the rules of community assembly and maintenance that, in large part, demand an understanding of the direct interactions among community members. Toward this end, we have developed a Poisson-multivariate normal hierarchical model to learn direct interactions from the count-based output of standard metagenomics sequencing experiments. Our model controls for confounding predictors at the Poisson layer and captures direct taxon-taxon interactions at the multivariate normal layer using an ℓ1 penalized precision matrix. We show in a synthetic experiment that our method handily outperforms state-of-the-art methods such as SparCC and the graphical lasso (glasso). In a real in planta perturbation experiment of a nine-member bacterial community, we show our model, but not SparCC or glasso, correctly resolves a direct interaction structure among three community members that associates with Arabidopsis thaliana roots. We conclude that our method provides a structured, accurate, and distributionally reasonable way of modeling correlated count-based random variables and capturing direct interactions among them.
1 Department of Statistics, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.
Surojit
S
Biswas
2 Department of Biology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.
Meredith
M
Mcdonald
2 Department of Biology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.
Derek S
DS
Lundberg
2 Department of Biology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.|3 Howard Hughes Medical Institute, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.|4 Department of Immunology, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.
Jeffery L
JL
Dangl
5 Department of Computer Science, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina.
Vladimir
V
Jojic
D000465:Algorithms; D019295:Computational Biology / Q000379:methods*; D003198:Computer Simulation; D030541:Databases, Genetic; D054892:Metagenome; D056265:Microbial Interactions; D008962:Models, Theoretical
conditional independence; hierarchical model; metagenomics; precision matrix; ℓ1-penalty