Table 1.

Glossary

16S rRNA gene sequence	Sequencing DNA within the hyper-variable regions of the 16S ribosomal RNA (16s rRNA) gene that enables identification of bacteria and archaea.
Genome	The complete set of genomic information for an organism including genes and non-coding sequences.
Epigenome	The collection of DNA modifications that affect gene expression and occur without direct alteration of the DNA sequence (e.g., DNA methylation, histone modification, and microRNAs).
Microbiome	The collection of commensal, symbiotic, and pathogenic microbes (e.g., bacteria, archaea, fungi, viruses) and their genomes in the human body.
Microbiota	All microbes that are found in a particular niche or region.
Metabolomics	High-throughput characterization of metabolites in body fluids (e.g., plasma, serum, exhaled breath condensate, and urine).
Metagenomic sequencing	Sequencing the total DNA of the ecosystem, with the advantage of providing information on the presence of bacteria, archaea, DNA viruses, eukarya, and their functionality.
Transcriptome	The complete set of RNA molecules produced in one cell or a population of cells.
Systems biology	An approach, by modeling diverse types of high-dimensional interactions, to developing a more comprehensive understanding of biology at multiple scales (molecular, cellular, tissue, organ, organism, and community).