Our second genome-human metagenome: how next-generation sequencer changes our life through microbiology.

Next-generation sequencing has greatly expanded our ability to query the identity and genetic composition of entire communities of microbial organisms. This area of research, known as metagenomics, does not rely upon culturing the individual organisms. Rather, the genetic material from the entire community is processed and sequenced simultaneously. From this sequence data, researchers are able to determine the relative population of organisms within the community as well as determine which genes and metabolic pathways are present and expressed in the microbial community. While these techniques have been applied to a wide range of environmental samples, metagenomics is also the focus of intensive research on human-associated microbial communities. The scope of these human metagenomics studies are quite varied, but all have a common goal of attempting to understand the important role that human commensal microbial communities play in health and disease. The early results from studying the human metagenome indicate a vital role that microbial communities play in immunity, health, and disease. Going forward, human metagenomics is a wide open field of research with many unanswered questions such as which factors are responsible for the variation of composition of an individual's microbiome, how does the microbiome respond to disturbance, and what beneficial functions are the microorganisms performing?