Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

LSU scientists develop new theory about human genome evolution by tracking ’stealth’ DNA elements

01.07.2005


A group of LSU researchers, led by biological sciences Professor Mark Batzer, have unraveled the details of a 25-million-year-old evolutionary process in the human genome. Their study focused on the origin and spread of transposable elements in the genome, many of which are known to be related to certain genetic disorders, such as hemophilia.

"Effectively, we’ve devised a theory that allows us to explain the origin of about half of all of the human genome," said Batzer.

Batzer was the principal investigator on the study, while LSU biological sciences graduate students Kyudong Han and Jinchuan Xing were the co-authors of the Genome Research paper on the discoveries. Other contributors to the research included graduate students Hui Wang and Dale Hedges, along with postdoctoral fellows Randall Garber and Richard Cordaux. Their findings were recently published in the journal Genome Research.



Batzer, the George C. Kent Professor of Life Sciences in the Department of Biological Sciences at LSU, and his group found that specific DNA sequences that appear to be in an inactive state for long periods of time may not be simply lying dormant after all. Instead, Batzer and his team have discovered that these elements played a crucial role in human evolution by secretly spawning hyperactive copies, giving rise to the most abundant family of transposable elements in the human genome, known as Alu elements. The study provides the first strong evidence for the evolution of Alu elements to date.

Alu elements are short DNA sequences capable of copying themselves, mobilizing through an RNA intermediate and inserting into another location in the genome. Over evolutionary time, this activity, known as "retrotransposition," has led to the generation of more than one million copies of Alu elements in the human genome, making them the most abundant type of sequence present. Because Alu elements are so abundant, comprising approximately 10 percent of the total human genome, they have been thoroughly examined and characterized in terms of their origin and sequence composition. What has remained elusive to scientists, however, is how these elements persist and propagate over time and influence human evolution. In an attempt to understand this process, Batzer and his colleagues examined a sub-family of Alu elements in the human genome known as the AluYb lineage, and compared these elements to those in the genomes of other primate species, including chimpanzees, bonobos, gorillas, orangutans, gibbons and siamangs. The AluYb sub-family accounts for approximately 40 percent of all human-specific Alu elements and is currently one of the most active Alu lineages in the human genome. Some AluYb elements are still actively mobilizing in the human genome, causing insertion mutations that have led to the development of a number of inherited diseases.

"These elements have contributed quite a bit to the diversity of human and non-human primate genomes, so it is very important to understand their origin and spread," said Batzer. "They cause about half a percent of all human genetic disorders."

According to Batzer, some of the genetic disorders related to these elements include hemophilia and some cancers. These disorders are caused by insertional mutation or by recombination between these elements, which is when elements that are near each other undergo a "recombination" and part of the genome is deleted in the process.

Batzer’s team demonstrated that the AluYb linage dates back approximately 18-25 million years. Their results also indicated that the AluYb sub-family underwent a major species-specific expansion in the human genome during the past 3-4 million years. This apparent 20-million-year stretch of general inactivity, followed by a sudden outburst of human-specific retrotransposition activity in the past few million years, led Batzer and colleagues to formulate a new theory for the evolution of Alu elements, termed the "stealth driver" model. In the "stealth driver" model, low-activity Alu elements are maintained in low-copy number for long periods of time and occasionally produce short-lived hyperactive progeny that contribute to the formation and expansion of Alu elements in the human genome.

Batzer explained that the exact purpose or function of these elements is still debated, but understanding their basic behavior and history could be crucial to finding answers in the future.

"Mobile elements make up a huge proportion of the human genome and understanding how these elements spread through the genome and how they contribute to genetic diversity is critical," said Batzer. "This research provides a fundamental insight into their spread and it has changed our opinion about what it takes to successfully spread through the genome."

For more information on the research, contact Batzer at 225-578-7102 or mbatzer@lsu.edu. More information can also found on the Batzer Laboratory Web site at batzerlab.lsu.edu.

The Web site for Genome Research is www.genome.org. Genome Research is an international, monthly, peer-reviewed journal published by Cold Spring Harbor Laboratory Press.

It is one of the five most highly cited primary research journals in genetics and genomics.

Rob Anderson | EurekAlert!
Further information:
http://www.lsu.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>