Microbial Genomics
at the U.S. Department of Energy

Primer on Microbial Genomics cont'd

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Why Study Microbes?

A vast and diverse microbial world occupies every nook and cranny of the globe, from the deepest depths of the ocean to the highest mountain peaks, living in the water, soil, and air that surround us, on and in the food that we eat, and on and within our own bodies. Microbes (including viruses, bacteria, fungi, protozoa, and microalgae) comprise most of the earth's biomass, maintain its environments, and hold the key to understanding the history of life on earth. Microorganisms have been present for over 3.8 billion years; we have known about their existence for over 300 years. Yet, incredibly, with some notable exceptions, we still know almost nothing about most of them. Now, with the advent of genomics (the study of an organism's entire DNA complement and its function), we are entering a new era of scientific discovery that holds great promise for understanding the complexities of the microbial world.

The DNA sequence of an organism's genome is often referred to as its genetic blueprint. Analysis of microbial genome data available thus far has already yielded surprising discoveries. In each microbial genome that has been sequenced, 40 to 50% of the putative genes encode proteins of unknown function, and 20 to 30% encode unknown proteins apparently unique to that species. Genomic analysis also suggests that less than 1% of the microbes on earth have been cultured and studied in the laboratory. Because of the unique properties of microbes already known and the almost incomprehensible number of microbes yet to be studied, these organisms represent an untapped and extremely valuable resource for the basic sciences, biotechnology, agriculture, human health, energy, and the environment.

The complete genome
sequence comprises
the fundamental "parts
list" for a microbe. The
genome also contains
information about
development and
responsiveness to the
environment.

 

While a genomic sequence can yield a great deal of information, genome sequencing is only the first step toward achieving an understanding of a microbe's biological capabilities. Learning how the genomic information predicts the functions of an organism's genes and therefore the organism's biology is a challenge that can now be met. Genome-enabled studies will lead to such breakthroughs as improved vaccines and better disease-diagnostic tools, identification of new drug and chemical targets in pathogens, discovery of new industrial catalysts, more accurate identification of microorganisms in situ in ecosystems from polar ice to soils to oceans, phylogenetic analyses of microorganisms, a general understanding of the earth's microbial diversity, and perhaps clues to the origins of life.

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Next: The Science

Text from The Microbe Project Report, December 2000, National Science and Technology Council Committee on Science, Subcommittee on Biotechnology, Interagency Working Group on Microbial Genomics, unpublished.