ARS | Publication request: The B73maize genome: complexity, diversity, dynamics

Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 30, 2009
Publication Date: November 20, 2009
Citation: Schnable, P., Ware, D., Fulton, R.S., Stein, J.C., Wei, F., Pasternak, S., Liang, C., Wing, R., Wilson, R., Zhang, L., Chia, J., Narechania, A. 2009. The B73maize genome: complexity, diversity, dynamics. Science. 326(5956):1112-1115.

Interpretive Summary: We are reporting the release of the sequence and analysis of corn, which is the largest and most repetitive plant genome, 85%, to be sequenced to date. Ninety nine percent of the gene annotations are found in the context of their respective chromosome positions based on the integrated genetic, optical and physical maps. Analysis of the genome sequence provides us some information on the evolution of the maize, specifically how retrotransposons have affected the size and organization as well as how the ancestor of modern maize, once contained two genomes, an ancestral polyploid, returned to a diploid state, demonstrating and uneven pattern of loss of genes between the two ancestral genomes. Comparative mapping between several other corn genomes suggests that each of these genomes may contain unique sequences that contribute to specific maize traits as well as the well known phenomenon of “heterosis” or “hybrid vigor”.

Technical Abstract: We report the nucleotide sequence of the maize (Zea mays cv. B73) genome, the largest and most structurally diverse of plants to be sequenced. ~32,540 genes are predicted, 99.8% of which are placed on chromosomes assembled from integrated physical, genetic and optical maps. Nearly 85% of the genome comprises over a thousand new families of transposons, that are dispersed non-randomly across the genome. The sequence reveals how retrotransposons might affect the composition, size and position of centromeres, and provides a snapshot of evolutionary processes that have returned an ancient allotetraploid to a genetically diploid state, including dramatically uneven gene losses between sister duplicated regions. Comparative sequencing revealed hundreds of haplotype-specific single-copy, expressed genes that may contribute to heterosis and the extraordinary phenotypic diversity of maize.