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:2/8/2017)... -- Report Highlights The global biosurgery market ... in 2016 at a compound annual growth rate (CAGR) ... - An overview of the global market for biosurgery. ... 2015 and 2016, and projections of compound annual growth ... on the basis of product type, source, application, and ...
(Date:2/7/2017)... Zimmer Biomet Holdings, Inc. (NYSE and SIX: ... at the LEERINK Partners 6th Annual Global Healthcare Conference ... February 15, 2017 at 10 a.m. Eastern Time. ... be accessed at http://wsw.com/webcast/leerink28/zbh .  The webcast will ... Biomet,s Investor Relations website at http://investor.zimmerbiomet.com . ...
(Date:2/6/2017)... Feb. 6, 2017 According to Acuity ... driving border authorities to continue to embrace biometric ... are 2143 Automated Border Control (ABC) eGates and ... at more than 163 ports of entry across ... 2016 achieving a combined CAGR of 37%. APC ...
Breaking Biology News(10 mins):
(Date:2/24/2017)... ... 2017 , ... Delpor, Inc. (Delpor), a biotechnology company focused on drug delivery, ... Health (NIMH) for the further advancement of the company’s 3-month olanzapine product ( DLP-119 ... to deliver therapeutic levels of olanzapine for a period of 3 months., “We are ...
(Date:2/24/2017)... , Feb. 24, 2017 Symic Bio, a ... a new category of therapeutics, announced today the completion ... in peripheral artery disease. The trial will evaluate the ... therapeutic, in the reduction of restenosis following angioplasty. ... development milestone for SB-030," said Nathan Bachtell , ...
(Date:2/24/2017)... 23, 2017 China Biologic Products, Inc. (NASDAQ: CBPO) ... biopharmaceutical company in China, today announced its financial results for ... Fourth Quarter 2016 Financial Highlights ... 21.7% in RMB terms, or increased by 13.6% in USD ... quarter of 2015. Gross profit increased by ...
(Date:2/23/2017)... 23, 2017 ... per share data, unaudited)Three Months Ended December 31,Twelve Months ... $         ...   89026%Aldurazyme Net Product Revenue ... Net Product Revenue  756025%297303(2)%Vimizim Net ...
Breaking Biology Technology: