Uncultured microorganisms present in environmental
samples, however, can be identified through the extraction
of nucleic acids (the metagenome) from such environmental
samples, as well as the isolation and sequencing of rRNA
or rDNA (genes encoding for rRNA). Samples from soils
and seawater are currently being investigated.39,40 Application
of whole-genome shotgun sequencing to environmentalpooled
DNA obtained from water samples collected in the
Sargasso Sea off the coast of Bermuda by the Venter group,
has indicated the presence of at least 1 800 genomic species,
which included 148 previously unknown bacterial phylotypes.40
The Venter group is also examining microbial
communities in water samples collected by the Sorcerer II
Global Ocean Sampling (GOS) expedition, and they have
reported that their data predict more than six million proteins,
nearly twice the number of proteins present in current
databases, with some of the predicted proteins bearing no
similarity to any currently known proteins and, therefore,
representing new families.41 Similar methods are also being
applied to the investigation of other habitats, such as the
microflora of insects42 and marine animals.