The maize genome

In the past 50 years, maize research has contributed to the basic understanding of life on earth and the underlying knowledge that has led to advancements in agriculture. Due to their large size, maize chromosomes provide good experimental tools in cytogenetics allowing the study of meiosis, chromosome pairing, and chromosome structure. Another useful biological feature of maize is that male and female flowers are separate structures allowing for easy reciprocal crosses and generation of inbred populations. Such features have contributed to gene dosage analysis and the first discovery of genomic imprinting in plants. More importantly, the size and structure of the maize ear has facilitated the analysis of rare variants in recombination and gene expression. In particular seed pigment accumulation has been the source for studying various alleles of genes involved in epigenetic control of gene expression, recombination, and transposition. Seed size has also been beneficial for the biochemical analysis of nutrients such as starch and storage proteins. These past studies contributed to major milestones in genetics and agronomic traits. However, interest in maize as a model for plant research has slowed in recent years because it lacked two key advantages found in other model plant species such as Arabidopsis - efficient DNA transformation and the complete sequence of its genome. The first obstacle has been overcome and transformation of the maize genome is now routine. As for the second, the plans for obtaining the complete genome sequence of maize are now in their advanced stages. Current knowledge about the organization and structure of the maize genome are summarized here.