A weedy, inedible member of the mustard family, related to broccoli and cauliflower, has become the first plant to yield the secrets of its primordial origins. In a computational research effort at Cornell University, the plant, Arabidopsis thaliana, was shown to contain genetic evidence of its emergence between 50 million and 200 million years ago.
The finding, say the Cornell researchers, will be invaluable to those usingArabidopsis as a genetic model for other plant species, unlocking genes for important traits in agricultural crops like corn, tomatoes and wheat.
The researchers report on their discovery in the latest edition of the journal Science (Dec. 15, 2000).
A decade ago, Arabidopsis was widely adopted by plant scientists as an easily manipulated model for other plants because it is simple to grow in the laboratory, has a short life cycle and has a small genome -- only about 140 million base pairs of DNA compared with wheat, which might have as many as 16 billion pairs. This year, the entire DNA sequence of the plant was completed, and for the first time researchers were able to understand the sequence of the 25,000 genes necessary for an organism to function as a flowering plant. Using this genome sequence -- which is in the public domain on the Internet -- the Cornell researchers used computers to sort through the plant's DNA and find its genetic roots.
"We can take the entire genome of one plant and look back at it," says Steven D. Tanksley, the Liberty Hyde Bailey professor of plant breeding at Cornell and an author on the paper. "We are going back into genetic time, and we can see what the ancient genome looked like. If we can understand what the ancestral gene content in one plant is, then we can use that to learn the gene content in other plants." Tanksley and the lead researcher, Todd Vision, a Cornell visiting scientist, explained that for many plant genomes there is a lot of empty materia
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