In the new study, genome analysis showed that one way that Tetrahymena adapts to diverse environments via gene duplication, a process that allows organisms to diversify pre-existing genes and adapt them for new functions. In the case of Tetrahymena, duplications appear to be concentrated in genes involved in sensing and responding to environment. From a small number of proteases (enzymes that degrade proteins), for instance, Tetrahymena has built an eating machine that allows it to digest nearly any protein it encounters.
Among its most quirky features, Tetrahymena has, inside each of its cells, two distinct nuclei, each with a different genome. Inside one nucleus, the "micronuclear" genome is reserved for sex and reproduction, remaining genetically silent during growth. Inside the second, working nucleus is the "macronuclear" genome, which expresses genes that govern behavior.
The current study sequenced the macronuclear genome, an impressively packaged bunch of coding genes, free of so-called junk DNA (noncoding sequences and other extraneous genetic elements) that litter the genomes of many organisms.
"Publication of the Tetrahymena genome marks the culmination of a remarkable collaboration within the research community," said Anthony Carter, Ph.D., of the National Institute of General Medical Sciences (NIGMS), which co-funded the project with the National Science Foundation (NSF). "Tetrahymena has a long and eminent history in the world of cell biology, and publication of its genome is likely to lead to further fundamental insights into how cells work."
Throughout the project, Eisen says, collaboration between researchers has been critical, including work by co-author Eduardo Orias of the University of California-Santa Barbara. The team emphasized open access to data, providing the genome sequence data to outside researchers, without restriction, since the project began in 2003. As a result, Tetrahymena researchers
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Contact: Kathryn Brown
kbrown@endpointcreative.biz
703-549-6641
The Institute for Genomic Research
28-Aug-2006