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Human Genome News Archive Edition
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Scientists Decode Genes of Microbe that Thrives in Toxic Metals
Understanding the genetic makeup of microbes that thrive in polluted environments may one day help scientists engineer bacteria to clean contaminants from soil. In a step toward that goal, the DOE Joint Genome Institute has released the draft DNA sequence of the toxin-tolerant Ralstonia metallidurans. Researchers at DOE's Brookhaven National Laboratory (BNL), in collaboration with a Belgian team, now are seeking to understand and manipulate the sequence. The research was funded in part by DOE's Microbial Genome Program.
This bacterium was first isolated in Belgium in 1976 from settling-tank sludge that was polluted with high concentrations of heavy metals. Examination revealed that, in addition to its chromosomal genes, Ralstonia has extra genetic material (plasmids) that house genes conferring resistance to the harmful effects of a wide array of heavy metals. Having the draft genome sequence will make manipulation of these naturally existing resistance factors more feasible. Scientists also are working on ways to limit the ability of bacteria to spread genes inadvertently so they will stay in the bacteria where they are put. This can be done by crippling Ralstonia's ability to transfer genes or by using host strains that normally do not transfer genes.
Potential future benefits include transferring Ralstonia's heavy-metal resistance genes to microbes with capabilities for breaking down other pollutants, thereby engineering strains with a combination of useful traits. Another possible application is to link Ralstonia's heavy-metal uptake to genes that cause bacteria to glow, or bioluminesce, when indicating the presence of heavy metals in the soil. The higher the concentration of metals, the brighter the glow.
"What we're doing is building on the diversity of biology," said BNL's John Dunn. "Here's a bacterium that potentially could be used as a tool to help us clean up the environment and to monitor how well we're accomplishing that goal."
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The Human Genome Project (HGP) was an international 13-year effort, 1990 to 2003. Primary goals were to discover the complete set of human genes and make them accessible for further biological study, and determine the complete sequence of DNA bases in the human genome. See Timeline for more HGP history.
Published from 1989 until 2002, this newsletter facilitated HGP communication, helped prevent duplication of research effort, and informed persons interested in genome research.