Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Puzzle of corn’s origins coming together


The scientific puzzle pieces are fitting together to form a definitive picture of the origin of corn, says a Duke University plant geneticist who has proposed that the world’s most important food crop originated in an ancient cross between two grasses.

Mary Eubanks described the latest evidence that corn, or maize, originated as a cross between teosinte and gamagrass, or Tripsacum, in a talk Friday, April 2, 2004, at a symposium on maize held at the annual meeting of the Society for American Archaeology ( in Montreal. Her research is supported by the National Science Foundation and the North Carolina Biotechnology Center.

Eubanks, an adjunct professor of biology, has developed evidence that modern corn, scientific name Zea mays, did not evolve solely from a Central American grass known as teosinte -- traditionally the most widely held theory. Rather, her experiments clearly demonstrate that corn arose from a serendipitously viable cross between teosinte and gamagrass.

Eubanks emphasized in an interview that her research has confirmed that teosinte was indeed one of corn’s ancestors, and that gamagrass was a critical genetic contributor. She contrasts her evidence with the former, highly controversial theory of the late biologist Paul Mangelsdorf, who espoused that teosinte was an offshoot of a cross between corn and Tripsacum rather than an ancestor of corn. "My hypothesis confirms that teosinte is an ancestor of maize, and that key genes were also contributed by gamagrass," she said. In her talk, Eubanks displayed examples of her crosses between species of teosinte and gamagrass that exhibit the evolution from the tiny spikes of teosinte seeds to the early versions of corn ears.

New evidence from other researchers that maize evolved very rapidly, perhaps over only a century, supports such a theory, said Eubanks. Rather than the long, slow progressive evolution from teosinte into maize, a fertile cross between teosinte and gamagrass could have relatively quickly yielded early versions of maize. In her talk, Eubanks displayed archaeological specimens of corn alongside matching segregates from experimental crosses between teosinte and gamagrass.

Eubanks also discussed her comparative DNA fingerprinting studies of teosinte and Tripsacum taxa, along with primitive popcorns from Mexico and South America. Those analyses of over a hundred genes in the taxa revealed that some 20 percent of the versions, called alleles, of specific genes found in maize are found only in Tripsacum. And, about 36 percent of the alleles in maize were shared uniquely with teosinte.

"These findings are by no means conclusive," said Eubanks. "We need to do a lot more sampling of the genetic diversity in different teosinte and Tripsacum species to further test this finding. But certainly, the preliminary evidence from this study supports the hypothesis that Tripsacum introgression could have been the energizing factor for the mutations that humans then selected to derive domesticated maize."

In such selections, theorized Eubanks, early humans would have selected -- from the wide range of plants that would result from such crosses -- those that had the most numerous and accessible seeds. Eventually, such selection would have resulted in the cob-like structure of today’s corn, she said.

Understanding the genetic origins of corn -- now the world’s single largest food crop-- is important both for production of new varieties and for preserving corn’s genetic heritage, said Eubanks.

"Because the crosses between teosinte and gamagrass bridge the sterility barrier between maize and Tripsacum, I’m now moving genes from gamagrass into corn," she said. "And we have developed drought-resistant and insect-resistant corn using conventional plant breeding methods."

For example, according to Eubanks, who is working with a commercial seed producer, test crops of some new hybrids have shown strong resistance to the billion-dollar bugs corn rootworm and European corn borer, along with corn earworm, another problematic corn pest.

"Understanding the genetic origins of corn and how people historically used corn could offer valuable insights for application to sustainable agriculture today," she said. "And finally, the gene pool underlying corn is part of our heritage that must be preserved if we are to retain the ability to solve agricultural problems such as new pests or the need for new farming methods."

Also, she noted, the scientific emphasis on corn is particularly timely because of recent findings that genetically altered corn is contaminating the native land races of maize and its wild relative teosinte currently in Mexico. This alteration of the natural gene pools of these genetic resources could have the effect of reducing the diversity of corn varieties, and compromise the ability to use those varieties as the basis for new crop strains.

According to Eubanks, the new drought and pest-resistant hybrids she and her colleagues have developed will undergo field tests this summer in the Midwest, followed by yield trials in winter nurseries, more field tests in the Midwest in 2005, and marketing seed in 2006.

Dennis Meredith | EurekAlert!
Further information:

More articles from Agricultural and Forestry Science:

nachricht Forest Management Yields Higher Productivity through Biodiversity
14.10.2016 | Technische Universität München

nachricht Farming with forests
23.09.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>