Arabidopsis thaliana is a small weed with big implications for plant science research. For several decades it has been used for genetic studies, because of the ease of producing genetic variants with altered traits of interest. Because it also has one of the smallest genomes of the higher plants, it has been the subject of an international effort to sequence all its genes. The fruits of this effort were published in December 2000. The first draft of the genome indicated that Arabidopsis has about 25, 000 genes, but the final number is likely to be nearer 30, 000. Information obtained from the study of the organization and function of the genes is proving to be useful in understanding gene evolution and function in crops with more complex genomes. Creative Gene Technology Ltd. is using Arabidopsis and cell cultures derived from it to identify genes and proteins that will be useful in plant breeding and agriculture.