Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Puzzle of corn’s origins coming together

05.04.2004


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 (www.saa.org) 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:
http://www.duke.edu
http://www.saa.org

More articles from Agricultural and Forestry Science:

nachricht New gene for atrazine resistance identified in waterhemp
24.02.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

nachricht Researchers discover a new link to fight billion-dollar threat to soybean production
14.02.2017 | University of Missouri-Columbia

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>