Introduction to Metagenomics

What is Metagenomics?

Genomics is the interdisciplinary field of science focusing on structure, function, evolution, mapping, and editing of genes. Historically, microbial genomics involved the isolation of microbes for genetic analysis through culturing methods to identify the genetic profile of species within a given sample. In recent years, Metagenomics has risen as a new frontier both as a research field and approach to circumvent the unculturability and genomic diversity of most microbes, the biggest roadblocks to advances in clinical and environmental microbiology.[1] The discipline of metagenomics represents the study of population genomics at the level of microorganisms, referencing the notion that a collection of genes from a given environment can be analyzed in a way analogous to that of a single genome, offering a powerful lens into the microbial world that has the potential to revolutionize the clinical sciences.[2]

History of Metagenomics

Conventional genomics began with the culturing of identifiable cells as a DNA source for analysis. However, early researchers investigating the preliminary notions of metagenomics hypothesized that the major weakness of conventional genomics is that groups of microorganisms cannot be analyzed if they cannot be cultured, and thus cannot be sequenced for genomic analysis. To overcome this hurdle in the field of genomics, the bacteria-specific 16S rRNA sequence was the main focus of early metagenomics as this sequence was relatively short, often conserved within a species, and generally different between species.[3] This led to the first report of isolating and cloning of bulk DNA from an environmental sample, published by Pace and colleagues in 1991.[4]

The Metagenomic Analysis Strategy