Metagenomics: A relief road to novel microbial genes and genomes

A huge quantum of the genetic and metabolic diversity of the biosphere is locked up within the microbial communities present in and on earth, as majority of earth's biomass comprises microbes. Ironically we cannot access more than 1% of this bioresource through routine culturing techniques as we have underestimated the power of microbes to resist culturing. This 1% of the microbial diversity accessed so far contributes to more than 80% of the industrial biotechnology at present and what miracles rest of the 99% can perform is anybody's guess. Metagenomics (also known as e-genomics, community genomics and environmental genomics) is clutch of molecular biology techniques used to hunt the culture resisting, yet- to- be cultured microbes. Metagenomics is a fruit born of the wedlock between modern molecular techniques and the idea, that microbial diversity can be analyzed by direct DNA isolation from environmental samples (metagenomic DNA), it's cloning, screening and sequencing. It would not be farfetched to conclude that after invention of microscope and culturing techniques, metagenomics is third big revolution in microbiology. Metagenomic revolution would not have been possible without the availability of low cost DNA sequencing services, bioinformatics tools and high through put screening techniques. This chapter will deal with the techniques used in metagenomics and achievements made so far along with future applications and challenges.