Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Capture Jumping Genes

08.02.2011
RIPs are alive and well — and moving — in the human genome

An ambitious hunt by Johns Hopkins scientists for actively “jumping genes” in humans has yielded compelling new evidence that the genome, anything but static, contains numerous pesky mobile elements that may help to explain why people have such a variety of physical traits and disease risks.

Using bioinformatics to compare the standard assembly of genetic elements as outlined in the reference human genome to raw whole-genome data from 310 individuals recently made available by the 1000 Genomes Project, the team revealed 1,016 new insertions of RIPs, or retrotransposon insertion polymorphisms, thereby expanding the catalog of insertions that are present in some individuals and absent in others. Their results appeared online October 27 in Genome Research.

Retrotransposons are travelling bits of DNA that replicate by copying and pasting themselves at new locations in the genome. Having duplicated themselves and accumulated over evolutionary history, transposable elements now make up about half of the human genome. However, only a tiny subfamily of these insertions known as LINE-1 (L1) is still active in humans. Line 1 insertions are able to mobilize not only themselves but also other pieces of DNA.

“In any individual, only between 80 to 100 retrotransposons are actively copying and inserting into new sites,” says Haig Kazazian, M.D., professor of human genetics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine. “We’re not only discovering where they are and who has which ones, but also finding out that they insert with a remarkable frequency: On the order of one in every 50 individuals has a brand-new insertion that wasn’t in their parents.”

The researchers recognized L1 retrotransposons — distinguishing them from the vast amount of fixed “fossil” transposable elements that litter the genome — because these actively jumping genes are human specific and almost exactly the same in sequence from one person to another.

“Our genome contains around half a million interspersed L1 sequences that have accumulated over evolutionary history, along with over a million more repeats, most of which were mobilized by L1 elements,” explains Adam D. Ewing, Ph.D., a postdoctoral fellow in Kazazian’s lab. “Since the vast majority of these are ancestral and therefore common to all humans and even some of our primate relatives, we can ignore them and focus on L1s that contain human-specific characters in their sequences. Those are the actively mobilized elements responsible for considerable genomic diversity among human individuals.”

The high frequency of these L1 insertions gives us a better idea about the extent of human diversity, according to Kazazian, whose 22-year focus on retrotransposons seeks to reveal how they alter the expression of human genes.

Just as the structural variants known as single nucleotide polymorphisms (or SNPs, pronounced “snips”) serve as markers for various diseases, the hope is that RIPs — which are up to 6,000 times bigger than SNPs, and therefore may have a stronger effect on gene expression — will correlate with disease phenotypes.

“In that same way that someone had to go out and find the SNPs, this study was about finding RIPs that remain active and continue to produce new insertions,” Kazazian says. “Now we have the background necessary to begin studies that may correlate these L1 insertions with everything from autism to cancer.”

Support for this research came from the National Institutes of Health.

Ewing and Kazazian are the authors of the paper.

On the Web:
Kazazian lab: http://humangenetics.jhmi.edu/index.php/faculty/haig-kazazian.html
Genome Research: genome.cshlp.org/

Maryalice Yakutchik | Newswise Science News
Further information:
http://www.jhmi.edu

More articles from Life Sciences:

nachricht The big clean up after stress
25.05.2018 | Julius-Maximilians-Universität Würzburg

nachricht Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

When corals eat plastics

24.05.2018 | Ecology, The Environment and Conservation

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>