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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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23 March 2005 (All day)
When it comes to plants and animals, biologists think of DNA as the sole storehouse of genetic information. A surprising new study challenges that notion. The mustard plant Arabidopsis thaliana sometimes ends up with its grandparents' good copy of a gene instead of the mutant ones belonging to its parents. So researchers are putting forth the radical proposal that plants contain an inheritable cache of RNA that can reverse evolution, undoing mutations and restoring a gene to its former glory.
Susan Lolle and Robert Pruitt of Purdue University in West Lafayette, Indiana first discovered that genes could go back in time about 3 years ago while studying a gene in A. thaliana called HOTHEAD. The surprise involved the reversal of a mutation. In plants with both copies of HOTHEAD mutated, the floral parts are all stuck together into a little ball. When such a plant self-fertilizes, its progeny inherit two copies of the mutated gene and all of them should have balls instead of flowers.
Instead, Lolle and Pruitt found that 1% to 10% of the offspring produced normal flowers, indicating that at least one copy of the mutant gene had reverted to the nonmutated wild-type. "It's something that Mendelian genetics has not prepared us for," says Pruitt. He and Lolle report the finding in the 24 March issue of Nature. Pruitt says RNA "templates" derived from the original gene and stored in the gametes are the best candidates for reverting the mutant gene to its original state.
The paper "suggests the existence of a unique genetic memory system that can be invoked at will," says Vincent Colot of the Plant Genomics Research Unit at Genopole in Evry, France. If confirmed and extended to animals, the new findings could profoundly affect biomedicine as well as population genetics. For example, geneticists trying to assess disease risk would have to take into consideration the makeup of this RNA memory, notes Emma Whitelaw of the University of Sydney, Australia.