Corn plants pose a tantalizing challenge to explorers on the genome frontier. In the 10,000 years since humans domesticated this crop from its wild relative teosinte, it has been led through immense variation depending on local food needs and farming practices.

I have seen corn plants in Mexico that were so tall farmers could harvest the grain on horseback. And most of us have eaten baby corn, popcorn, white corn, yellow corn, speckled corn, etc. Variation abounds around the world.

The upshot is that corn’s genome is nearly as complex as the human genome.

Now a University of Minnesota plant scientist and colleagues are making news with discoveries of quirks in the corn genome. With help from the newly released DNA sequence of the common corn strain B73, U of M plant biologist Nathan Springer and colleagues from Iowa State University, Roche NimbleGen of Wisconsin and the University of Florida reported surprising findings in the latest issues of the journal Science and PLoS Genetics.

By comparing the genetic sequence of B73 with that of another inbred strain, Mo17, the team discovered structural variations that could help custom tailor crops for specific traits such as high protein content for human consumption or high glucose content for biomass fuel.

Differences in the genomes of the two corn strains were far greater than the researchers had expected, almost as great as the difference between humans and chimpanzees. Such differences can help explain at the molecular level the advantage of a hybrid -- how corn created by combining genes from two different parents can be superior to either parent.