For the first time, scientists have determined the complete genetic structure of the smallest free-living organism known--Mycoplasma genitalium, a bacterium that invades and lives in cells lining human urinary and genital tracts.
Researchers at the School of Medicine joined those at the Institute for Genetic Research in Rockville, Md., and Johns Hopkins University to conduct the analyses.
"Our results are an important first step toward understanding the minimal number of genes required for a living system to grow independently and cause disease," said Kenneth F. Bott, professor of microbiology and immunology.
Besides Bott, University team members were Clyde A. Hutchison III, Kenan professor of microbiology and immunology; Ping-chuan Hu, professor of pediatrics; Scott Peterson, a former doctoral student in the genetics curriculum; and Thomas Lucier, a postdoctoral researcher.
The 29-member team found that the organism consists of 580,070 base pairs of nucleotides, which form the rungs of the long, twisted ladder shape of DNA, Hutchison said. They also found a total of only 470 "coding regions," or genes, required for replication, transcription, DNA repair, metabolism and other vital cell functions.
"This work gives us for the first time the ability to compare different organisms to see which elements they have in common and which are different," he said. "That gives us an idea of what genes are required to have a free-living cell."
The research was supported partly by a U.S. Department of Energy cooperative agreement and a grant to the institute from Human Genome Sciences, a biotechnology company.
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