Organism’s Complete DNA Code Mapped for First Time
Learning for the first time the entire DNA code for a free-living organism will help science solve basic puzzles about disease and how to fight it, an expert says.
David Kingsbury of Johns Hopkins University said Friday that breaking the DNA code for the bacterium Hemophilus influenzae “will help us know how all bacteria work.”
“From a fundamental biological viewpoint, this is of great significance,” said Kingsbury, head of the human genome database at Hopkins.
Two researchers, J. Craig Venter of the Institute for Genomic Research in Gaithersburg, Md., and Hamilton Smith of the Hopkins School of Medicine announced this week that they had found the complete sequence for the DNA for Hemophilus influenzae. This is the first time that the entire genome has been decoded for an organism that can live without a host.
The researchers also have completed the code for another bacterium, Mycoplasma genitalium, Kingsbury said.
Venter and Smith announced the accomplishment Wednesday night at a meeting of the American Society for Microbiology.
Kingsbury said that by knowing the sequence of such organisms, scientists now will be better able to find weak points in a microbe’s structure and to develop drugs that exploit those weaknesses.
One important prospect, he said, is to learn why one strain of bacterium can be so dangerous while its close relative is benign.
By knowing the gene sequence of this group of microbes, Kingsbury said, it may now be possible to solve the puzzle of virulence.
Venter and Smith reported that the Hemophilus influenzae has a DNA sequence of 1,830,121 base pairs, the chemical units that make up the genome of an organism.
The gene sequences of some viruses are known, but viruses are much simpler than bacteria in DNA structure because they lack the ability to live independently.
Kingsbury said that Hemophilus influenzae does not actually cause influenza, but earned its name because it frequently is a secondary infection in people who have the flu, which is caused by a virus. He said it often causes serious or even lethal pneumonia in the elderly and is seen most often in children with upper respiratory diseases.
