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NSF PR 99-73 - December 15, 1999
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Scientists Report First Complete DNA Sequence of Plant
Chromosomes
Scientists involved in an international effort to sequence
the entire genome of Arabidopsis thaliana have
reported the first complete DNA sequence of a plant
chromosome in the December 16, 1999, issue of the
journal Nature. The results provide
new information about chromosome structure, evolution,
intracellular signaling and disease resistance in
plants. The research conducted by U.S. participants
was funded in large part by the National Science Foundation
(NSF), as well as the U.S. Department of Agriculture
and U.S. Department of Energy.
U.S. and European scientists in the Nature
article report the complete DNA sequence of two of
the five chromosomes of Arabidopsis. Working together,
a U.S. consortium led by Cold Spring Harbor Laboratory
scientist Richard McCombie, and the European Union
Arabidopsis Genome Sequencing Consortium led by Michael
Bevan of the John Innes Centre (Norwich, UK), completed
the sequence of chromosome 4. A team of scientists
at The Institute for Genomic Research in Rockville,
Maryland, determined the sequence of chromosome 2.
Together, these chromosomes comprise roughly one-third
of the Arabidopsis genome. Scientists predict that
sequencing of the entire genome will be completed
by the end of 2000.
Says Mary Clutter, assistant director of NSF for biological
sciences, "Scientists can use this information to
understand the function of genes in important plant
processes. These studies will ultimately lead to the
development of plants that are more nutritious, produce
useful chemicals, withstand flood and drought, or
can grow on marginal lands. Considering how much we
were able to learn about the genome organization at
the chromosome level, we can look forward to many
new discoveries next year when the entire genome is
completed."
Arabidopsis thaliana has emerged as a powerful
tool for research in plant molecular biology and genetics.
The short generation time and relatively compact genome
of Arabidopsis make it an ideal model system for understanding
numerous features of plant biology, including ones
that are of significant value to agriculture, energy,
environment, and health.
"We are three or four years ahead of schedule," says
McCombie, referring to the current progress toward
the goal of completing the Arabidopsis genome sequencing
project. "This is due largely to the fact that throughout
this endeavor, all the groups involved have worked
hard to share information."
Analysis of the chromosome 4 sequence and comparison
of this sequence to that of chromosome 2 revealed
several interesting features. The most striking is
the extent to which individual genes and entire blocks
of chromosomal regions have been duplicated in the
Arabidopsis genome. For example, a very large stretch
of DNA (4.6 million base pairs) is duplicated on chromosomes
2 and 4. This duplication represents approximately
one-quarter of the total length of each of these chromosomes,
and its existence in plants supports the emerging
view that large scale intragenome duplications may
significantly impact genome evolution in many organisms.
Note to Broadcasters: B-roll package available.
Contact Dena Headlee at 703-306-1070 or (pager 1-800-937-5249);
email: dheadlee@nsf.gov
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