Botany of this species is encoded by about 135 million base pairs of DNA, forming one of the smallest genomes among flowering plants. "Arabidopsis" was the first plant to have its genome sequenced, in 2000. The sequencing of some other relatively small genomes, of rice ("Oryza sativa") and "Brachypodium distachyon", has made them important model species for understanding the genetics, cellular and molecular biology of cereals, grasses and monocots generally. Model plants such as "Arabidopsis thaliana" are used for studying the molecular biology of plant cells and the chloroplast. Ideally, these organisms have small genomes that are well known or completely
Plant genome assembly products were used to clone remaining gaps, and YACs allowed the characterization of telomere sequences. The resulting sequenced regions were 115.4 Mb of the 125 Mb predicted size of the genome and a total of 25,498 of protein-coding genes. To sequence and assemble the genome of Oryza Sativa (japonica), the same strategy was used. For Oryza Sativa a total of 3,401 mapped clones in a minimum tiling path were selected from the physical map and assembled. One of the most important crops in the world, maize (Zea mays), is the last plant genome project primarily based on Sanger BAC-by-BAC strategy.