Navigation Links
If junk DNA is useful, why is it not shared more equally?
Date:1/31/2011

The presence of introns in genes requires cells to process "messenger RNA" molecules before synthesizing proteins, a process that is costly and often error-prone. It was long believed that this was simply part of the price organisms paid for the flexibility to create new types of protein but recent work has made it clear that introns themselves have a number of important functions. And so attention is gradually shifting to asking why some organisms have so few introns and others so many.

It seems likely that new introns are added to DNA when double-stranded DNA breaks which may arise from a variety of mechanisms are not repaired "correctly" but the newly created ends are instead joined to other fragments of DNA. Farlow and colleagues at the Institute of Population Genetics of the University of Veterinary Medicine, Vienna reasoned that introns may be lost by a similar mechanism. An examination of areas of DNA where introns are known to have been lost in organisms such as worms and flies provides support for their idea.

DNA breaks may be treated in one of two ways: correct repair (by a relatively time-consuming process known as "homologous recombination") or the rapid and error-prone joining of non-homologous ends. The two pathways are essentially separate and can compete with each other for DNA breaks to work with. The scientists at the University of Veterinary Medicine, Vienna now suggest that species-specific differences in the relative activity of these two pathways might underlie the observed variation in intron number.

The theory represents a fundamental change in the way we think about the evolution of DNA. Evolution has seen periods of large scale intron loss alternating with periods of intron gain and this has been interpreted as the result of changing selection pressure. However, the rates at which single species have gained and lost introns throughout evolution have been found to vary in parallel, consistent with Farlow's notion that the two processes are related. The new theory provides an alternative interpretation: changes in the activities of the "homologous" and "non-homologous" pathways for repairing DNA breaks could cause introns to be lost faster than they are gained, or vice versa.

The idea is consistent with what we currently know about intron numbers, which range from a handful in some simple eukaryotes to more than 180,000 in the human genome. And as Farlow says, "Linking intron gain and loss to the repair of DNA breaks offers a neat explanation for how intron number can change over time. This theory may account for the huge diversity we seen in intron number between different species."


'/>"/>

Contact: Dr. Ashley Farlow
ashley.farlow@vetmeduni.ac.at
43-125-077-4333
University of Veterinary Medicine -- Vienna
Source:Eurekalert

Related biology news :

1. Shared survival mechanism explains why good nerve cells last and bad cancer cells flourish
2. Periodontitis and myocardial infarction: A shared genetic predisposition
3. Bolivian rainforest study suggests feeding behavior in monkeys and humans have ancient, shared roots
4. Freshwater sustainability challenges shared by Southwest and Southeast, researchers find
5. Hard-to-find fish reveals shared developmental toolbox of evolution
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:1/31/2017)... CAMBRIDGE, Mass. , Jan. 31, 2017 /PRNewswire-USNewswire/ ... develop novel therapies for the treatment of bacterial ... generation set of antibacterial candidates from Pro Bono ... the increased prevalence of multi-drug resistant forms of ... by Cantab Anti Infectives Ltd, a PBB group ...
(Date:1/25/2017)... , Jan. 25, 2017 The Elements ... Management (IAM) lifecycle is comprised of a comprehensive ... the purpose of maintaining digital identities and providing ... and applications. There are significant number of programs ... time to time by optimizing processes and changing ...
(Date:1/21/2017)... 20, 2017 Research and Markets has announced ... report to their offering. ... The global voice recognition biometrics market to grow ... The report covers the present scenario and the growth prospects ... the market size, the report considers the revenue generated from the ...
Breaking Biology News(10 mins):
(Date:2/21/2017)... Orlando, FL (PRWEB) , ... February 21, 2017 ... ... that enables healthcare organizations to build connected digital health applications, announced a partnership ... will enable users to seamlessly connect to many clinical systems while keeping data ...
(Date:2/21/2017)... Francisco, CA (PRWEB) , ... February 21, 2017 ... ... pleased to announce that Dr. Trevor Heritage has joined its executive team to ... revolutionary system designed to provide insights to help improve the diagnosis and treatment ...
(Date:2/21/2017)... ... 21, 2017 , ... VetStem Biopharma, Inc ., announced ... in Poway, California. Based upon 12 years of knowledge gained by following ... VetStem constructed and validated a state-of-the-art GMP stem cell manufacturing plant. This ...
(Date:2/21/2017)... LOS ANGELES , Feb. 21, 2017  Lexus, a returning ... its role as the official and exclusive automobile partner of the ... annual spring race. The 2017 Amgen Tour of ... five-year commitment and feature some of the best professional cycling teams ... , May 14-20. The four-day Amgen Breakaway from Heart ...
Breaking Biology Technology: