The extensive suite of molecular-based approaches developed over the past decade has enabled the field of metagenomics, the study of uncultured microorganisms. Paramont to metagenomic analysis is use of high-throughput DNA sequencing technologies, which with the advent of low cost next-generation methods is transforming metagenomics. The application of metagenomics, to both global environments and microbes associated with a living host, has facilitated study of the functional ecology of environmental microorganisms. Novel functional genes and environmental functional signatures can be retrieved using metagenomics, and these can form the basis of hypothesis driven analyses of uncultured microorganisms. A with any technology, the daunting task is to understand and apply the growing number of metagenomic sequences in the context of microbial ecology and evolution.
from Metagenomics: Theory, Methods and Applications by Diana Marco, Caister Academic Press ISBN: 978-1-904455-54-7
and Environmental Molecular Microbiology by Wen-Tso Liu and Janet K. Jansson, Caister Academic Press ISBN: 978-1-904455-52-3