Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Going with the grain: A tale of rice’s smallest chromosome

06.06.2003


’Finished’ sequence reveals twice as many genes, cereal similarity



Behold a grain of rice. Inside are thousands of cells; within each cell are 12 chromosomes; and on rice’s smallest chromosome, No. 10, are about 3,500 genes and more than 22 million base pairs, the links in the chain of DNA.
So, what’s the big deal about rice’s smallest chromosome?

There are several, according to a report in the June 6 issue of the journal Science. Upon close examination, chromosome 10 has about twice as many genes as were predicted when an international consortium announced draft genome sequence in the same journal last December. An organism’s genome consists of the entire genetic code held in its DNA.



Of potentially greater significance, a detailed look at chromosome 10 shows that the genome map of rice is similar to other grains, particularly sorghum and maize.

The project, led by Rod A. Wing of the University of Arizona and C. Robin Buell of The Institute for Genomic Research (TIGR), was funded by the U.S. Department of Agriculture, National Science Foundation, National Institutes of Health, and the Department of Energy. A portion of chromosome 10 was also sequenced by the Plant Genome Initiative at Rutgers.

The work demonstrates the value of pursuing the full sequence in detail, said Judith Plesset, a program director in NSF’s Directorate for Biological Sciences, which supported the project. "One of the lessons here is, ’Don’t think you know everything simply because you’ve done the draft,’" she said.

According to TIGR’s Buell, getting from the draft to the finished version is painstaking and costly because the process "is not automated to any large extent" and it requires considerable lab work by an extended team of research associates.

The resulting view, however, is immensely clearer. "Like looking at the cosmos through a regular telescope, and then looking at it through the Hubble telescope," Buell said.

Focusing on rice matters because, according to the report, rice (Oryza sativa) has been cultivated for more than 9,000 years and remains a major food staple for more than half the human population.

While rice feeds half the world, its relatively simple genome helps scientists understand the genetics of other plants. According to the Science report, "Rice is considered a model system for plant biology largely due to its compact genome (430 million base pairs, or Mb, on its 12 chromosomes) and evolutionary relationships with other large-genome cereals, such as sorghum (750 Mb), maize (2,500 Mb), barley (5,000 Mb) and wheat (15,000 Mb)."

Added NSF’s Plesset, "We can use rice as a reference for understanding the organization, structure and function of much larger genomes such as maize and wheat. Scientists can use a rice gene to find its counterpart in any of the cereal genomes."

Seeking to identify the roles of the chromosome’s genes by combing through molecular databases, Buell, Wing and their colleagues compared chromosome 10’s proteins with those of another model plant, Arabidopsis, a member of the mustard family whose genome has been completely sequenced and extensively documented. Matches were found for about two-thirds of the proteins, indicating some of the specific genes responsible for enzyme production, binding of nucleic acids, cell growth and maintenance, cell communication, immunity, development and other functions and processes.

On the chromosome’s "short arm," however, they found very little that matched Arabidopsis. Instead, there they found an abundance of heterochromatin, a stretch of highly compacted DNA with few genes among it, a chromosomal substance for which the biological function is unknown.

Though much more detailed than the draft, this version is not completely finished and has seven gaps, representing about 4 percent of the total sequence.

"This," Plesset said, "is a result of the limitation of sequencing technology. As new technologies become available, these gaps will be filled."

The work reported in Science is a part of the international collaboration to sequence the entire rice genome completely. Two of the other 12 rice chromosomes, numbers 1 and 4, have also been essentially "finished," and published by the Japanese and the Chinese groups, respectively. A full sequence for chromosome 3 is expected to be announced by the end of 2003.

Sean Kearns | NSF
Further information:
http://www.nsf.gov
http://www.nsf.gov/od/lpa

More articles from Life Sciences:

nachricht Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg

nachricht Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Electrode materials from the microwave oven

19.10.2017 | Materials Sciences

New material for digital memories of the future

19.10.2017 | Materials Sciences

Physics boosts artificial intelligence methods

19.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>