The researchers have sequenced the genetic information or "genome" of Methanococcus jannaschii, a single-cell microorganism known as an archaeon (meaning "ancient" in Greek). M. jannaschii is a methane-producing thermophile discovered at the base of a Pacific Ocean thermal vent.
"This gives us fundamental information about life on Earth, its evolution and diversity. These findings represent the scientific equivalent of opening a new porthole on Earth and discovering a wholly new view of the universe," said Dr. J. Craig Venter, director of TIGR, headquartered in Rockville, MD. "In decoding the genetic structure of archaea, we were astounded to find that two-thirds of the genes do not look like anything we've ever seen in biology before. This brings to closure the question of whether archaea are separate and distinct life forms," Venter said.
Secretary of Energy Hazel R. O'Leary congratulated the researchers on behalf of the Clinton administration, "This accomplishment contributes profoundly to scientists' fundamental understanding of life. The biotechnology industry is also watching closely to see how this breakthrough can help develop new sources of renewable energy, clean up the environment and improve human health."
Scientists previously believed that a microorganism with such a small genome (1,760 genes) would contain much more known genetic information, but instead the unexpected genetic information is of great interest because it will allow scientists to understand more about the operation and functions of the cell, the fundamental unit of all life.
Besides archaea, the other two major groups of life are bacteria and the more complex "eukaryotes" which include plants, animals and humans. Formerly known as archaebacteria, archaea are believed to have separated from true bacteria over three billion years ago. By comparing the genes of M. jannaschii to those of bacteria and humans, scientists hope eventually to better understand the evolution of all three branches of life. Discovered 20 years ago, archaea were originally believed to live only at extreme environmental conditions of temperature and pressure, but are now thought to be far more common and to make up a significant part of the world's biomass. They are suspected of playing important but still unknown roles in the earth's ecology, including its carbon and nitrogen cycles.
Discovered in 1983, M. jannaschii lives only at high temperatures (optimally at 85oC or 185oF) so its molecules are heat stable. This would be a useful property for many industrial and pharmaceutical processes. The complete genome of M. jannaschii offers the opportunity to develop heat-resistant products such as new detergent additives or stable enzymes for the textile and chemical industries.
Understanding how M. jannaschii produces methane could help researchers learn to genetically engineer organisms to produce quantities of methane for use as a source of renewable energy and synthetic chemicals. M. jannaschii also appears to produce metal-binding proteins that transport toxic compounds out of the cell, with potential applications for the concentration and clean-up of toxic wastes.
The U.S. Department of Energy funded the research as part of its microbial genome program. The $5 million annual program has as its goal to sequence the genetic information of microorganisms of interest to the department's energy and cleanup programs. M. jannaschii, with 1.7 million DNA base pairs or nucleotides, is the second of those genomes to be completed. M. jannaschii is the third microorganism ever to be sequenced completely and published; the previous two were also done by TIGR researchers, one with support from DOE. DOE funds the microbial genome program as a complement to its support of the human genome program, an international project to decode the estimated 80,000 human genes. DOE and its predecessor agencies have a long history of support for genetic research growing out of their legislative mandate to understand the health effects of nuclear energy, radiation and the byproducts of other forms of energy production.
TIGR is a non-profit arm of Human Genome Sciences Inc., located in Rockville, MD.