Figure 12.8 Using Transposon Mutagenesis to Determine the Minimal Genome
Scientists are in the process of defining the minimal genome necessary for the survival and reproduction of a number of different types of bacteria. One method for doing so involves transposon mutagenesis, in which genes are mutated at random by transposon mobilization and insertion to determine which genes are nonessential under laboratory growth conditions. Under the direction of Craig Venter, the minimal genome of Mycoplasma genitalium has been determined and reported to consist of only 482 protein-coding genes. More recently, a team of researchers led by S. Dusko Ehrlich in France have reported that the bacterium Bacillus subtilis needs just 271 genes to live in an experimental environment. Ultimately, researchers are hoping to create a “minimal organism,” and they are rapidly making advances towards achieving this goal. The technology to accomplish this task is not far beyond current methods, and, in fact, is the main goal of at least one private company, Synthetic Genomics, Inc. This company aims to engineer cell level bio-factories to serve as a tool in the energy industry. Certainly, this technology has the potential to benefit society in a number of ways. However, it also raises a number of ethical, social, and religious issues. Further, there is a real danger of abuse of this technology, particularly with regard to bioterrorism and environmental problems. Clearly, the potential impact of this type of research and development will require further public discussion.
Original Papers
Hutchison, C. A., S. N. Peterson, S. R. Gill, R. T. Cline, O. White, C. M. Fraser, H. O. Smith, and J. C. Venter. 1999. Global Transposon Mutagenesis
and a Minimal Mycoplasma Genome. Science 286: 2165–2169.
http://www.syntheticgenomics.com/pdf/MinimalMycoplasma.pdf
http://www.ncbi.nlm.nih.gov/pubmed/10591650
See also:
Glass, J. I. et al. 2006. Essential genes of a minimal bacterium. Proceedings of the National Academy of Sciences 103: 425–430.
http://www.pnas.org/content/103/2/425.full.pdf+html
http://www.ncbi.nlm.nih.gov/pubmed/16407165
Lartigue, C. et al. 2009. Creating Bacterial Strains from Genomes That Have Been Cloned and Engineered in Yeast. Science 325: 1693–1696.
http://www.scienceonline.org/cgi/reprint/sci;325/5948/1693.pdf
Gibson, D. G. et al. 2010. Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome. Science 329: 52-56.
http://dx.doi.org/10.1126/science.1190719
Links
Pray, L. 2008. Transposons: The Jumping Genes. Nature Education 1(1)
http://www.nature.com/scitable/topicpage/Transposons-The-Jumping-Genes-518
Adams, J. 2008. Simple Viral and Bacterial Genomes. Nature Education 1(1)
http://www.nature.com/scitable/topicpage/Simple-Viral-and-Bacterial-Genomes-635
Genomics: GTL: Estimation of the Minimal Mycoplasma Gene Set Using Global Transposon Mutagenesis and Comparative Genomics
http://genomicscience.energy.gov/pubs/2005abstracts/venter.pdf
Genome News Network: Another Minimal Genome: Microbe Needs Just 271 Genes
http://www.genomenewsnetwork.org/articles/04_03/minimal.shtml
NCBI: Annual Reviews Collection: How Many Genes Can Make a Cell: The Minimal-Gene-Set Concept
http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=arev&part=A1667
Synthetic Genomics, Inc.
http://www.syntheticgenomics.com/about/
Cho, M. K., D. Magnus, A. L. Caplan, D. McGee, and the Ethics of Genomics Group. 1999. Ethical Considerations in Synthesizing a Minimal Genome. Science 286: 2087–2090.
http://www.scienceonline.org/cgi/content/full/286/5447/2087
Nature news: E. C. Hayden. 2009. Scientists devise new way to modify organisms.
http://www.nature.com/news/2009/090820/full/news.2009.847.html
Kimball’s Biology Pages: The Origin of Life: Creating Life
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/AbioticSynthesis.html#CreatingLife
The New York Times: Researchers Say They Created a “Synthetic Cell”
http://www.nytimes.com/2010/05/21/science/21cell.html
Cho, M. K. and D. A. Relman. 2010. Synthetic “Life”, Ethics, National Security, and Public Discourse. Science 329: 38-39.
http://dx.doi.org/10.1126/science.1193749
Nature news: A. Katsnelson. 2010. Researchers start up cell with synthetic genome
http://dx.doi.org/10.1038/news.2010.253
Nature news: R. Kwok. 2010. Genomics: DNA’s master craftsmen
http://dx.doi.org/10.1038/468022a