A crop of genetic variants in maize

Re-sequencing of diverse varieties of maize from around the world is reported by three studies published online this week in Nature Genetics. The studies identify millions of genetic variants that should be useful for maize geneticists and breeders to further improve crop yield.

Maize is an important cereal crop, but its genome is very large-about the size of the human genome-and substantially more diverse than the human genome. It has been technically challenging to comprehensively characterize the enormous wealth of genomic diversity present in this crop.

Doreen Ware and colleagues performed re-sequencing of 103 maize lines, including 60 improved maize lines, 23 maize landraces and 19 wild relatives of maize. They also generated sequence for a sister genus of maize, Tripsacum dactyloides (Eastern gamagrass). They identified 55 million single nucleotide polymorphisms, which is a large resource for the maize genetics and breeding community. Jeffrey Ross-Ibarra and colleagues analyzed this dataset to identify regions of the genome that were selected for during the initial phase of domestication, as well as subsequent improvement of maize landraces to modern maize. They identify a large number of genes that appear to have been selected for during the transformation of wild to modern maize.

Finally, Jinsheng Lai and colleagues performed re-sequencing of 278 maize lines. They performed comprehensive characterization of sequence variation present in these diverse maize lines, and identified a number of genetic regions that display evidence of selection during maize domestication.