Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rutgers geneticists redefine the nature of hybrid corn

14.07.2003


Scientists at Rutgers, The State University of New Jersey, have unlocked an important door to understanding one of the most important crops in the world – corn. Researchers at Rutgers’ Waksman Institute of Microbiology have redefined the nature of heterosis or hybrid vigor, the phenomenon underlying corn’s remarkable success. Heterosis is the robustness seen in hybrids when different lines are crossed and result in higher yields than either of the parental lines would produce themselves.



Maize (corn) dominates agriculture in the United States, where, according to the National Corn Growers Association, 9 billion bushels are produced annually at a value of more than $21 billion. No crop rivals its total grain yield or the diversity of its uses. Virtually all corn varieties grown today are hybrids. Understanding the genetic basis of heterosis could revolutionize our thinking about genetics and pave the way to even stronger, healthier or more productive strains.

Rentao Song and Joachim Messing of Rutgers’ Waksman Institute of Microbiology discuss their findings in a paper published in the July 22 issue of the Proceedings of the National Academy of Science. The paper is currently available online.


Waksman scientists are deeply involved in the Maize Genome Sequencing Project, an initiative to determine the order and position of the genes on the plant’s large and complex chromosomes. The heterosis investigations were a logical extension of the project.

Song and Messing took a region of a chromosome they had accurately mapped and compared it in two strains of maize – to each other, to hybrid crosses, and to corresponding regions in close relatives of maize – two kinds of rice. They also analyzed gene expression in the maize – whether genes were turned on or off – comparing the maize strains and hybrids.

They found that the same genome interval of the two maize varieties and their hybrids, all members of the same species, was substantially different in each, both in size and content. "Genes are missing or added, as are whole sequence segments that contain more than one gene," wrote Song and Messing. The genetic differences were striking.

When they examined, for instance, the same genome interval of two rice strains, they found far less difference between them – what would typically be expected of any strains from the same species based on pure genetic data.

The significance here is that crossing two different maize strains having dramatically different genetics would be expected to produce a hybrid differing considerably from either parent. The hybrid would have accumulated genes from both parents – genes that complement each other, setting the stage for heterosis. The hybrid should exhibit characteristics with twice the vigor of the parents. To prove that this was really a source of hybrid vigor, the scientists looked at how the genes were expressed in the hybrid offspring and in the parents.

The results showed that the combination of the radically different parental genomes in the offspring produced a hybrid genome where genes absent in one parent were supplied by the other. Messing explained that this "dominance complementation," as it is termed, might logically be viewed as the basis for hybrid vigor. However, the expression data demonstrated a vigor exceeding what would be expected from the simple addition of previously missing genes.

"The ’whole’ – the hybrid offspring – turned out to be much greater than the sum of the parts," said Messing. "This led us to conclude that different regulatory factors from other parts of the genome were also operating in a situation we call ’overdominance.’

"What we are finding is a synergism that is much more than just combining the two parents," he continued. "Not only do the hybrids benefit from genes added by both parents, but their inheritance also includes additional regulatory factors. These two sources of heritable information may well constitute the binary system of the genetic world.

"We got something super – much more than we anticipated. We had heterosis with a firm, verifiable genetic foundation."

Joseph Blumberg | EurekAlert!
Further information:
http://www.rutgers.edu/

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>