Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Rice centromere, supposedly quiet genetic domain, surprises


Probing the last genomic frontier of higher organisms, an international team of scientists has succeeded in sequencing a little understood - but critical - genetic domain in rice.

In doing so, the group, led by Jiming Jiang, a professor of horticulture at the University of Wisconsin-Madison, and C. Robin Buell of the Institute for Genomic Research in Rockville, Md., has exposed a supposedly barren region of a rice chromosome known as the centromere. The work, published in the current (Jan. 11) online editions of the journal Nature Genetics, reveals for the first time that a native centromere, typically composed of enormous spans of indecipherable, non-coding DNA, contains active genes.

The feat promises to help fill in a key genetic void and enhance the scientific understanding of chromosomes, the molecular structures that are found in all animal and plant cells, and are the essential carriers of hereditary information, enabling the processes of cell division and replication.

At a practical level, the work is a necessary step toward science’s long-term goal of creating an artificial chromosome for plants, says Jiang. Such a tool, now available only for humans and yeast, would be an invaluable aid to scientific study and a precursor to precision plant engineering techniques.

"This is a significant step," says Jiang. "This is the first centromere to be sequenced at this level for any higher organism."

The centromere of rice, says Jiang, lent itself to sequencing because, unlike centromeres from other organisms, it is of a manageable size. Most centromeres are composed of vast stretches of what was once called "junk DNA," seemingly nonsense genetic sequences with no apparent coding function.

"They’re humongous," Jiang explains. The DNA within centromeres is "highly repetitive, and it is resistant to mapping, cloning and sequencing," he says.

The finding of active genes was a surprise, says Jiang. The newly discovered rice centromere genes, whose functions are unknown, belie the idea that the centromere is an enormous molecular wasteland composed only of non-coding DNA.

"This is the first time active genes have been found in a native centromere," according to Jiang. "There are at least four active genes" interspersed in the DNA of the rice centromere.

The centromere is one of three essential elements of every chromosome. In addition to centromeres, chromosomes are composed of telomeres, genetic sequences that cap and protect the ends of chromosomes, and a site known as the "origin of replication" or "ori," where the actual business of genetic replication takes place. With all three components in hand, it would be possible, in theory, to construct an artificial chromosome.

In most organisms, including the critical model organisms such as the mouse, the fruit fly Drosophila melanogaster and the plant Arabidopsis thaliana, centromeres have proved to be nearly intractable for sequencing.

The rice centromere is accessible, says Jiang, because the centromere of rice chromosome 8 lacks the vast tracts of repetitive non-coding DNA common to most species. And that there are active genes in the centromeres of rice provides an intriguing window to evolution. It may be that the centromere sequenced by the team led by Jiang is in its early evolutionary stages.

The evolutionary progression of the centromeres, Jiang suggests, may be analogous to how temperate forests evolve from more diverse ecosystems to climax forests where a single species of tree dominates. In the rice centromere, it may be that evolution has not yet purged active genes to be replaced by the long and repetitive blocks of DNA that mark the centromeres of most organisms.

In addition to Jiang and Buell, co authors of the Nature Genetics paper include lead author Kiyotaka Nagaki, also of UW-Madison; Zhukuan Cheng of the Chinese Academy of Sciences; Shu Ouyang, Mary Kim and Kristine M. Jones of the Institute for Genomic Research; and Paul B. Talbert and Steven Henikoff of the Howard Hughes Medical Institute at the Fred Hutchinson Cancer Research Center on Seattle.

- Terry Devitt (608) 262-8282,

Terry Devitt | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht When fat cells change their colour
28.10.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Aquaculture: Clear Water Thanks to Cork
28.10.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

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...

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

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>