Applications of weighted association networks applied to compositional data in biology.

: Next generation sequencing technologies have generated, and continue to produce, an increasingly large corpus of biological data. The data generated are inherently compositional as they convey only relative information dependent upon the capacity of the instrument, experimental design, or technical bias. There is considerable information to be gained through network analysis by studying the interactions between components with a system. Network theory methods using compositional data are powerful approaches for quantifying relationships between biological components and their relevance to phenotype, environmental conditions, or other external variables. However, many of the statistical assumptions used for network analysis are not designed for compositional data and can bias downstream results. In this mini-review, we illustrate the utility of network theory in biological systems and investigate modern techniques while introducing researchers to frameworks for implementation. We overview (1) compositional data analysis, (2) data transformations, and (3) network theory along with insight on a battery of network types including static-, temporal-, sample-specific-, and differential-networks. The intention of this mini-review is not to provide a comprehensive overview of network methods, rather introduce microbiology researchers to (semi)-unsupervised data-driven approaches for inferring latent structures that may give insight into biological phenomena or abstract mechanics of complex systems. This article is protected by copyright. All rights reserved.