The simultaneous sequencing of the genomes present in a specified community of microorganisms. A sample is taken of the species living in specific habitat, and the DNA isolated from that sample is subjected to shotgun sequencing (q.v.). Advanced computer programs then allow the sequenced fragments to be assembled into groupings that represent the genomes of the most common species in the sample. About 99% of all known bacteria have never been cultured in laboratories, and genomes have been constructed for only a small subset of the cultured species. Community genome sequencing allows the construction of genomes for species that have never been cultured. Such a study was made of samples from a biofilm in a California mine. The film forms a scum on the surface of a pool that has formed in a shaft that extends 1,400 feet into Iron Mountain. The water is hot (106°F), very acidic, and rich in toxic metals. There is little light or oxygen. Eighty mbp of DNA was recovered from a sample of this biofilm and assembled into five genomes. The two most complete genomes belonged to extremophiles (q.v.). These species were placed in the Leptospirillum and Ferroplasma groups of the Archaea. See Chronology, 2004, Tyson et al., Venter et al.; Genome Sizes and Gene Numbers.
Subjects: Genetics and Genomics.