An international effort to sequence the entire genome of the plant species Arabidopsis thaliana is now complete. This first-ever complete genome sequence from a plant has many implications for biology, medicine, agriculture, and the environment because it will enable detailed studies of the entire genetic structure of plants to be carried out. Such studies will yield a great deal of new information about the gene products that are involved in many aspects of plant growth and development, and how these gene products carry out their functions.
Despite its status as a diminutive relative of the mustard plant, Arabidopsis thaliana is a powerful tool in plant molecular biology and genetics. The short generation time and relatively compact genome of Arabidopsis (a flowering plant) make it an ideal model system for understanding numerous features of plant biology, including ones that are of great pharmaceutical or agricultural value.
The sequencing studies, reported in the December 14, 2000, issue of the journal Nature, provide new information about chromosome structure, evolution, and gene organization in plants. Among the many new genes discovered were several involved in disease resistance and intracellular signaling, as well as homologs of a number of human disease genes. Perhaps the most surprising result of these studies, and related studies published last year (see below), is the extent to which vast chromosomal regions have been duplicated in the Arabidopsis genome. In fact, the new study indicates that the evolution of Arabidopsis involved a whole-genome duplication, followed by gene loss and additional, extensive local gene duplications.
The Arabidopsis genome was found to contain 25,498 genes encoding proteins from 11,000 families, similar to the functional diversity of the fruit fly Drosophila and the soil nematode worm C. eleganstwo other multicellular organisms whose genomes have been completely sequenced. However, Arabidopsis has many
Contact: Peter W. Sherwood, Ph.D.
Cold Spring Harbor Laboratory