U.S. scientists uncover maize's full genetic code

13:17, November 20, 2009      

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In a massive survey of genetic diversity in maize, also known as corn, 150 researchers across the United States, have developed a full gene map that should pave the way to significant improvements in the plant that is a major source of food, fuel, animal feed and fiber around the world.

The new map, a special type of gene map known as a haplotype map, charts genetic diversity and recombination across the genome of 27 inbred lines of maize. The research team, led by Washington University in St. Louis, Missouri, will report its findings in the Nov. 20 issue of the journal Science.

Researchers found that Maize (Zea mays L.), with its genome of estimated 32,000 genes distributed along 10 chromosomes, is about 70 percent the size of the human genome.

In constructing the haplotype map, the researchers identified several million genetic variations - or polymorphisms - in the DNA sequence among the 27 maize inbred lines, as well as 10-fold to 30-fold variation in the rates at which genes recombine.

"Having the complete genome in hand will make it easier to breed new varieties of corn that produce higher yields or are more tolerant to extreme heat, drought, or other conditions," said senior author Richard Wilson, director of Washington University's Genome Center.

"We are hopeful that the information that this haplotype map reveals about the genetic diversity of maize will provide a foundation for efforts to understand maize evolution and the genetic basis of complex traits that may prove key to maize improvement," said Jeffrey Ross-Ibarra of the University of California, Davis.

The project, which began in 2005, cost 29.5 million U.S. dollars and was funded by the National Science Foundation and the U.S. Departments of Agriculture and Energy.

Corn is the third most abundant cereal crop, after rice and sorghum, researchers said. The United States is the world's top producer of corn with 200 million tons a year, or 44 percent of the world's output.

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