2.3.2.6 Future prospects: potential of metagenomic approaches
While culture-dependent techniques have been highly successful in the identi"cation of novel bioactive compounds from marine microorganisms, the advent of deep sequencing technologies such as pyrosequencing has revealed a huge diversity of microorganisms in various niches in the marine environment, the majority of which cannot be accessed by traditional culturing techniques. Metagenomics involves the cloning of total community DNA, including DNA from uncultured microorganisms, and subsequent sequence-based or function-based analyses. Sequence-based metagenomic approaches rely on the comparison of cloned DNA to known sequences from databases, while functionbased metagenomic approaches involve screening library clones for a phenotype, such as antibacterial or anti-quorum sensing activity. These metagenomic approaches allow access to natural products produced by microorganisms which cannot be cultured, effectively increasing the mining potential of the marine environment.