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An
international research group decided in 1996 to sequence the entire
genome of Arabidopsis thaliana (thale cress), which contains
five chromosome pairs. This small perennial plant, a member of the
mustard family, is the main model system for laboratory studies in
basic plant biology. European and North American research teams recently
completed the sequence of chromosomes 2 and 4. Work on the remaining
three chromosomes is proceeding rapidly and should be concluded by
late summer 2000. The French teams, in Evry, Grenoble, and Perpignan,
are working on the sequence of chromosome 3, with the support of the
EU Biotechnology Programme.
The researchers in this international project have sequenced a total
of 37.1 million DNA base pairs, which is nearly all of chromosomes
2 and 4, and more than a quarter of the Arabidopsis genome.
The scientists have identified 7,781 protein-coding genes, which is
approximately one third of the plant's total genes, estimated to be
26,000. Their initial findings reveal a number of new genes, repetitions
of individual genes, and large chromosomal regions.
This plant was chosen in 1996 for the sequencing project because it
has a relatively small genome and is easy to grow in the laboratory.
Most of the genes in Arabidopsis are also found in the genomes
of plants that are very distant in evolutionary terms, such as wheat
or rice, where they carry out the same functions, i.e., genes controlling
resistance to disease, to cold, synthesis of vitamins, lipids, etc.
Determining the complete sequence of a plant genome represents a major
step and will provide a basis for research into other plants and organisms.
Researchers suspect that the genes of plants may have more in common
with human genes than animal genes and human genes have in common.
The sequence of the Arabidopsis genome provides a wealth of
data available for research.
References:
- Lin X. et al.
Sequence and analysis of chromosome 2 of the plant Arabidopsis
thaliana. Nature, 1999, vol. 402, pp. 761-768.
- Mayer et al.
Sequence and analysis of chromosome 4 of the plant Arabidopsis
thaliana. Nature, 1999, vol. 402, pp. 769-777.
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