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:4/5/2017)... 5, 2017  The Allen Institute for Cell Science ... a one-of-a-kind portal and dynamic digital window into the ... the first application of deep learning to create predictive ... lines and a growing suite of powerful tools. The ... and future publicly available resources created and shared by ...
(Date:4/4/2017)... 4, 2017   EyeLock LLC , a leader ... United States Patent and Trademark Office (USPTO) has issued ... linking of an iris image with a face image ... the company,s 45 th issued patent. ... timely given the multi-modal biometric capabilities that have recently ...
(Date:3/30/2017)... , March 30, 2017 The research ... system for three-dimensional (3D) fingerprint identification by adopting ground breaking 3D ... a new realm of speed and accuracy for use in identification, ... an affordable cost. ... ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... 12, 2017 , ... The Blavatnik Family Foundation and the ... of the 2017 Blavatnik Regional Awards for Young Scientists. Established in 2007, ... the New York Academy of Sciences to honor the excellence of outstanding postdoctoral ...
(Date:10/12/2017)... ... , ... AMRI, a global contract research, development and manufacturing ... and quality of life, will now be offering its impurity solutions as a ... requirements for all new drug products, including the finalization of ICH M7 earlier ...
(Date:10/11/2017)... ... ... eye wash is a basic first aid supply for any work environment, but most personal ... rinse first if a dangerous substance enters both eyes? It’s one less decision, and likely ... dual eye piece. , “Whether its dirt and debris, or an acid or alkali, getting ...
(Date:10/11/2017)... the Netherlands and LAGUNA HILLS, Calif. ... The Institute of Cancer Research, London ... use MMprofiler™ with SKY92, SkylineDx,s prognostic tool to risk-stratify patients ... trial known as MUK nine . The University of ... trial, which is partly funded by Myeloma UK, and ICR ...
Breaking Biology Technology: