A complete genome is the ultimate "parts list" for an organism. The availability of complete genomes is now upending the traditional research approach. Previously, no alternative existed but the "reductionist" approach—to dissect an organism, its systems, and its component parts down to their simplest elements. With all the parts for a microbe now in hand (although many still have unknown functions), we now must reverse direction and do biology differently than in the past, to take a more "reconstructionist" approach. Today, we are like children with a new set of Lego blocks, dreaming of all that we can build with them if only we could understand how the pieces fit together. Obtaining the parts lists for an increasing number of microbial genomes has also launched explorations at a new level, ushering in the now flourishing field of comparative genomics.

Microbes, which make up most of the Earth's biomass, have evolved for some 3.8 billion years. They have been found in virtually every environment, surviving and thriving in extremes of heat, cold, radiation, pressure, salt, acidity, and darkness, often where no other forms of life are found and where the only nutrients come from inorganic matter. It is thought that less than 1% of all microbial species have ever even been described, since the repertoire of known species is highly dependent on the ability to culture them and most microbes are difficult to grow in the lab. (Most microbes are not responsible for diseases in humans, animals, or plants, which makes them "silent" to investigations.) The diversity and range of their environmental adaptations means that microbes have long ago "solved" many problems for which scientists are still actively seeking solutions.

To aid in carrying out its missions, DOE initiated the Microbial Genome Program in late 1994 as a spinoff of its then 8-year-old Human Genome Program. DOE missions include (besides supporting innovative high-impact and peer-reviewed science) a range of difficult challenges such as environmental waste cleanup, energy production, and biotechnology. Moreover, DOE also supports research into global climate processes, a field in which scientists are beginning to appreciate the role of microbial life. Thus the MGP not only will contribute to established DOE missions but also will generate novel insights into both the biological underpinnings of climate change and the microbial role in the overall processing of carbon and nitrogen on Earth. These capabilities can then be added to long-known uses of microbes in the brewing, baking, dairy, and other industries.

This first Microbial Genome Program report displays the significant accomplishments of this young program. While the program has supported the sequencing of 11 microbial genomes to date, with an additional 17 in various stages of progress, the real measure of this program's impact is that at least five other U.S. government agencies have more recently initiated microbial sequencing efforts. It is significant that all these agencies are establishing the firm policy that the sequence data will be made public for unrestricted use by the scientific community.

But the real impact of the Microbial Genome Program will come from the delivery of new science, new insights, and new approaches to the difficult challenges that DOE faces in carrying out its varied and demanding missions. We anticipate enormous progress as the vast repertoire of microbial genes, honed by billions of years of evolution and hitherto largely concealed from us, becomes available. An exciting future lies ahead.

Daniel Drell, Program Manager
Microbial Genome Program
Office of Biological and Environmental Research
U.S. Department of Energy
301/903-6488, daniel.drell@science.doe.gov