Plant genomes are characterised by large differences in their size, and this is often caused by genome duplications leading to polyploidy, an important factor in plant evolution. Analysis of the sequence has revealed a dynamic genome. Genome sequence reveals a past duplication of the Arabidopsis genome and subsequent gene loss, thus analysis of the Arabidopsis genome reveals important mechanisms of genome evolution. Plant genomes are methylated and this plays a major role in regulating heritable changes in chromatin function and gene expression. Arabidopsis centromeres, the most extensively sequenced of any higher eukaryote, provide a way to understand replication and segregation and design new ways of genetic engineering.
Plants synthesise all their nutrients from air water and minerals in the soil.
This remarkable metabolic capacity is due in part to genes derived from a photosynthetic bacteria related to present day cyanobacteria, denizens of hot pools. These genes have evolved by transfer to the nucleus. Arabidopsis contains the largest number of genes analysed to date. It is initially strange to consider that a simple plant has nearly twice as many genes as a fruit fly.