The new maize genome study showed that:

• Though a substantial amount of diversity was lost during domestication, new diversity has arisen since domestication in the form of novel mutations;

• Hundreds of identified genes appear to have played a role in domestication of maize from the wild, and many of these genes also appear to have been important for modern breeding;

• Selection applied during initial domestication appears to have been much stronger than selection applied more recently during maize breeding; and

• Modern strategies of breeding for hybrid vigor have been accompanied by marked changes in gene expression in maize.

The companion study was led by Doreen Ware, a U.S. Department of Agriculture-Agricultural Research Service computational biologist at Cold Spring Harbor Laboratory, New York.  That study used a sophisticated population genetics-based scoring model to untangle the complexity of the maize genome.  Through the study, the researchers:

• Identified more than 55 million genetic markers in the maize genome and demonstrated that the genome is continuously changing;

• Discovered that it is common for genes to be present or absent -- or to occur in varying numbers -- in both wild and domesticated maize, and these variations are associated with important agricultural traits; and

• Found that there is substantial continuity of gene content between maize relatives, suggesting that environmental adaptations such as perennialism, and frost and drought tolerance might be transferred from wild relatives into domesticated maize.

The international collaboration that produced the two studies was coordinated by Edward Buckler, a U.S. Department of Agriculture-Agricultural Research Service research geneticist at Cornell University.

Lead authors of the UC Davis-led study include Matthew Hufford, Joost van Heerwaarden and Tanja Pyhäjärvi, of UC Davis; and Xun Xu of BGI, China. Other researchers on the study include Chi Song, Jun Wang, Gengyun Zhang and Shuang Yang, all of BGI, China; Jer-Ming Chia and Doreen Ware (USDA-ARS) of Cold Spring Harbor Laboratory, New York; Reed Cartwright of Arizona State University Tempe; Ed Buckler (USDA-ARS), Robert Elshire and Jeffrey Glaubitz, at Cornell University, New York; Shawn Kaeppler at the University of Wisconsin, Madison; Jinsheng Lai of China Agricultural University, Beijing; Peter Morrell, Nathan Springer, Ruth Swanson-Wagner and Peter Tiffin, all of the University of Minnesota; and Michael McMullen and Kate Guill of the USDA-ARS at the University of Missouri, Columbia.