September 15, 2006 Scientists have decoded a tree genome for the first time, with findings that could have wide-ranging consequences for botanists as well as foresters. A team of over 100 researchers from the United States, Canada, France, Sweden, Belgium, Germany, Austria, and Finland worked together to decipher the genetic code of the black cottonwood tree.

The team was led by Gerald Tuskan at Oak Ridge National Laboratory and Daniel Rokhsar at the Joint Genome Institute; their results are published in the September 15 issue of Science.

The black cottonwood, a type of poplar, was selected because of the ease in adding or removing its genes, as well as its fast growth rate, according to Science. Its speedy growth is a boon to scientists, who can get results from their experiments in less than a year, and also to commercial interests, who value the trees for wood, paper, and as a potential source of ethanol.

Researchers speculate that this genome sequencing will allow the black cottonwood to create poplar varieties suited for specific purposes. According to the Associated Press, a certain variety might produce better paper, for example, or absorb more carbon dioxide to alleviate global warming. Another variety could be used to create ethanol, the biofuel typically made from corn.

According to an accompanying article in Science, the black cottonwood, or Populus trichocarpa, is only the third plant genome to be sequenced. By comparing the cottonwood's DNA with that of the other sequenced plant genomes—rice and the small flowering annual Arabidopsis—researchers discovered that the poplar's whole genome has been duplicated at least three times, most recently 60 million years ago.

The duplicate genes will offer clues about the process of natural selection, as a gene's copy can evolve a different function, Science reported. The functions of half the poplar's genes are currently unknown.

For more on the researchers' findings, go to www.sciencemag.org.

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