Arabidopsis Information Service, established in 1964. The first International Arabidopsis Conference was held in 1965, in Göttingen, Germany. In the 1980s, A. thaliana started to become widely used in plant research laboratories around the world. It was one of several candidates that included maize, petunia, and tobacco. The latter two were attractive, since they were easily transformable with the then-current technologies, while maize was a well-established genetic model for plant biology. The breakthrough year for A. thaliana as a model plant was 1986, in which T-DNA-mediated transformation and the first cloned A. thaliana gene were described. Genomics Nuclear genome Due to the small size of its genome, and because it is diploid, Arabidopsis thaliana is useful for genetic mapping and sequencing — with about 157 megabase pairs and five chromosomes, A. thaliana has one of the smallest genomes among plants. It was long thought to have the smallest genome of all flowering plants, but that title is now considered to belong to plants in the genus Genlisea, order Lamiales, with Genlisea tuberosa, a carnivorous plant, showing a genome size of approximately 61 Mbp. It was the first plant genome to be sequenced, completed in 2000 by the Arabidopsis Genome Initiative. The most up-to-date version of the A. thaliana genome is maintained by the Arabidopsis Information Resource. The genome encodes ~27,600 protein-coding genes and about 6,500 non-coding genes. However, the Uniprot database lists 39,342 proteins in their Arabidopsis reference proteome. Among the 27,600 protein-coding genes 25,402 (91.8%) are now annotated with "meaningful" product names, although a large fraction of these proteins is likely only poorly understood and only known in general terms (e.g. as "DNA-binding protein without known specificity"). Uniprot lists more than 3,000 proteins as "uncharacterized" as part of the reference proteome. Chloroplast genome The plastome of A. thaliana is a 154,478 base-pair-long DNA molecule, a size typically encountered in most flowering plants (see the list of sequenced plastomes). It comprises 136 genes coding for small subunit ribosomal proteins (rps, in yellow: see figure), large subunit ribosomal proteins (rpl, orange), hypothetical chloroplast open reading frame proteins (ycf, lemon), proteins involved in photosynthetic reactions (green) or in other functions (red), ribosomal RNAs (rrn, blue), and transfer RNAs (trn, black). Mitochondrial genome The mitochondrial genome of A. thaliana is 367,808 base pairs long and contains 57 genes. There are many repeated regions in the Arabidopsis mitochondrial genome. The largest repeats recombine regularly