The genomes of particular nonhuman organisms such as Arabidopsis thaliana have been studied for a number of reasons including the need to improve sequencing and analysis techniques. These nonhuman genomes also provide powerful sets of data against which to compare the human genome.
For example, Arabidopsis uses a chemical, glutamate, much as it is used in the human brain. The plant has genes that encode for glutamate receptors. In the human brain, glutamate acts as a chemical messenger, playing a role in acquiring and storing memories, and possibly contributing to certain mental health ailments. Glutamate also acts as a messenger in plants, communicating the presence of light and regulating light-dependent processes.
The Arabidopsis thaliana genome has been found to have 100 million base pairs to date and is estimated to have 25,000 genes to date. The sequencing of this genome was still in progress as of June 2000.