Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New technique will produce a better chromosome map

09.05.2007
Researchers at the University of Illinois have developed a simple and economical technique for imaging and mapping fruit fly chromosomes. This new approach will enable them to construct the first accurate map of the chromosomes and tease out the secrets hidden in their stripes.

Their work appears online May 6 in advance of publication in the journal Nature Methods.

Fruit flies are well suited for chromosome studies because some of their cells contain gigantic, “polytene” chromosomes, each built up of more than 1,000 parallel copies of DNA strands. When stained, condensed, dark bands and lighter regions (interbands) give the chromosomes a striped appearance.

For more than 70 years, cytogeneticists have used a hand-drawn map of the bands of fruit fly polytene chromosomes, with the shape and location of these structures only vaguely delineated. This map, first published in 1935, and generations of light and electron micrographs have yielded an imprecise guide to the chromosomes.

... more about:
»Chromosome »MAP »structure »technique

Traditional methods of chromosome preparation have limited usefulness for those hoping to sort out how the bands and interbands relate to the underlying genetic sequence, said cell and developmental biology research specialist Dmitri Novikov, who developed the new technique. The genome of the fruit fly, Drosophila melanogaster, was sequenced in 2000, and yet its relationship to chromosome structure remains unclear.

“Since we want to know what genes are involved in the development of different structures in living systems, this is the first structure to look at,” Novikov said. “This is the starting point: the appearance of the genes themselves.”

Cell and developmental biology professor and lead investigator Andrew S. Belmont and visiting scientist Igor Kireev, of Moscow State University, are co-authors on the paper. Belmont is in the U. of I. Institute for Genomic Biology and the Center for Biophysics and Computational Biology.

Current methods for preparing polytene cells for viewing under a light microscope involve using a thumb, pencil, forceps or other instrument to maneuver and press the cells between a glass coverslip and slide. Only about 10 percent of the slides processed this way provide useable images and even those rarely offer crisp structural details, Novikov said.

The new approach includes two components: the use of mechanical devices to spread and flatten the cells, and the application of computer-based image processing to analyze hundreds of examples of the same chromosomes. With so many crisp images to analyze, computer algorithms can accurately calculate the number, shape and location of the chromosome bands.

“Two researchers might see the same image differently,” said graduate research assistant Mert Dikmen, who uses computer vision technologies under the supervision of Beckman Institute professor Thomas Huang to analyze the images. “Our system will give an impartial estimate of the band location. It will not be researcher-dependent. It will be objective.”

To improve chromosome spreading, researchers use a rotary tool that vibrates the coverslip surface for several minutes. A simple mechanical vise applies up to two tons of force to each slide, rendering the preparations very thin and high in contrast. This allows the production of much clearer, information-packed images.

The technique has other advantages: Because it relies on light microscopy, it is faster and more economical than electron microscopy, with comparable or superior results.

With a more accurate chromosome map, researchers will next use fluorescent immunostaining of proteins that bind to specific DNA sequences. These landmarks will help them tease out the relationship of the sequence to the physical structure.

The new approach will allow scientists to answer fundamental questions about chromosome structure, Novikov said. Such questions have relevance across species.

Editor’s note: To reach, call 217-333-8372; e-mail: novikov@uiuc.edu.

Diana Yates | EurekAlert!
Further information:
http://www.uiuc.edu

Further reports about: Chromosome MAP structure technique

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Stretchable biofuel cells extract energy from sweat to power wearable devices

22.08.2017 | Power and Electrical Engineering

New technique to treating mitral valve diseases: First patient data

22.08.2017 | Medical Engineering

IVAM Marketing Prize recognizes convincing technology marketing for the tenth time

22.08.2017 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>