Big Time for Small Genomes

A new field of research has emerged that would have been unthinkable to most people as recently as 2 years ago. There is no generally accepted name for this discipline, but “genome-based microbiology” seems to be appropriate. As indicated in the title of the recent meeting “Small Genomes: Sequencing, Functional Characterization and Comparative Genetics” (The Institute for Genomic Research Genomic Series, Hilton Head, SC, January 25–28, 1997), this field capitalizes on complete sequences of “small” genomes, which effectively means genomes of unicellular organisms. The information derived from complete genome sequences and particularly from their comparative analysis is used explicitly to study the biology of the microbial cells and to infer phylogenetic conclusions. At the meeting, approximately one-half of the talks still belonged to the genomic era, that is, they were progress reports on projects aimed at complete sequencing of a particular genome or, in some cases, several genomes. The remaining talks ventured into the postgenomic era and presented either genome comparison studies or functional analysis based on the knowledge of a complete genome sequence. As a substantive indication of the importance attached to the new field, the meeting featured brief presentations by representatives of three major funding agencies, National Institutes of Health (USA), Department of Energy (USA), and the Wellcome Trust (UK), all of which provide significant support for further development and worldwide coordination of the microbial genomics effort.

In his introductory overview of the small genome sequencing efforts, J. Craig Venter (The Institute for Genomic Research, Rockville, MD, hereafter TIGR) indicated that even though the number of completely sequenced genomes is currently very small, the trend toward exponential (if not faster) growth is apparent—two complete genomes appeared in 1995, four in 1996, and it is realistic to expect eight or more in 1997. Therefore, there is no doubt that …