Figure 1. Multi-omic and gnotobiotic approaches to host-microbial interaction.

High-throughput analyses of host and microbial DNA, RNA, proteins and metabolites can be performed using metagenomics, metatranscriptomics, metaproteomics and metabolomics, respectively, to investigate interrelationships between host and microbial factors. Hypotheses that emerge from multi-omic studies can be tested using gnotobiotics through colonization of germ-free mice with characterized microbial consortia or human gut microbiota. This approach will help to elucidate effects on host biology of factors that modulate the gut microbiota including environment (e.g., geography, hygiene), diet, host genotype, physiological states (e.g., pregnancy) and disease states.