Featured Research

from universities, journals, and other organizations

Parasites or not? Transposable elements in DNA of fruit flies may be beneficial

Date:
February 3, 2012
Source:
Veterinärmedizinische Universität Wien
Summary:
Many living organisms suffer from parasites, which use the hosts’ resources for their own purposes. The problem of parasitism occurs at all levels right down to the DNA scale. Genomes may contain up to 80% “foreign” DNA but details of the mechanisms by which this enters the host genome and how hosts attempt to combat its spread are still the subject of conjecture. Nearly all organisms contain pieces of DNA that do not really belong to them.

Many living organisms suffer from parasites, which use the hosts' resources for their own purposes. The problem of parasitism occurs at all levels right down to the DNA scale. Genomes may contain up to 80% "foreign" DNA but details of the mechanisms by which this enters the host genome and how hosts attempt to combat its spread are still the subject of conjecture. Important new information comes from the group of Christian Schlötterer at the University of Veterinary Medicine, Vienna.

Related Articles


The findings are published in the journal PLoS Genetics.

Nearly all organisms contain pieces of DNA that do not really belong to them. These "transposable elements," so called because they are capable of moving around within and between genomes, generally represent a drain on the host's resources and in certain cases may lead directly to disease, e.g. when they insert themselves within an essential host gene. The factors that govern the spread of transposable elements within a population are broadly understood but many of the finer points remain unclear. New work at the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) may pave the way to a more profound knowledge of the intracellular battle that is constantly being played out between the host and invading DNA.

Robert Kofler and Andrea Betancourt in Schlötterer's group at the Vetmeduni Vienna's Institute of Population Genetics used new sequencing technologies to examine the variation in transposable elements within a population of fruit flies. Similar investigations had been undertaken previously but the scientists incorporated a number of refinements to ensure that their analysis considered both known and previously unknown sites of insertion. For the first time, the researchers were able to catalogue all the transposable elements in a population of flies. And importantly they were also able to determine how frequently transposable elements occur at each particular site of insertion.

The findings were dramatic. The flies contain transposable elements at a large number of sites in the genome, although many insertion sites are affected in relatively few individuals. These are presumably sites of recent insertion and only the future will tell whether the elements are maintained there. Some older insertion sites are widespread but the majority seem not to be "fixed" in the population. In other words, most transposable elements are somehow purged before they become established. Schlötterer sums up the results by stating that "the genome is like a record of past wars between hosts and the parasitic DNA. There have been waves of attacks and the majority of them have been repelled, with only few transposable elements managing to survive and spread throughout the population."

Even more surprisingly, the scientists found about a dozen sites of insertion that were more frequent in the population than would be expected from their age (assessed via a different method). It seems, then, that there is positive selection for transposable elements at these sites, suggesting that insertion has a beneficial effect on the host. Such an effect had previously been shown for two insertions that give increased resistance against insecticides and these cases were refound by Schlötterer's analysis. The functions of the genes closest to the remaining insertions are highly diverse, so how the transposable elements may benefit the flies is unclear. As Schlötterer puts it, "perhaps we shouldn't really think of transposable elements as parasites at all. They represent a way for organisms to increase their genetic repertoire, which may be advantageous in helping them meet future challenges."


Story Source:

The above story is based on materials provided by Veterinärmedizinische Universität Wien. Note: Materials may be edited for content and length.


Journal Reference:

  1. Robert Kofler, Andrea J. Betancourt, Christian Schlötterer. Sequencing of Pooled DNA Samples (Pool-Seq) Uncovers Complex Dynamics of Transposable Element Insertions in Drosophila melanogaster. PLoS Genetics, 2012; 8 (1): e1002487 DOI: 10.1371/journal.pgen.1002487

Cite This Page:

Veterinärmedizinische Universität Wien. "Parasites or not? Transposable elements in DNA of fruit flies may be beneficial." ScienceDaily. ScienceDaily, 3 February 2012. <www.sciencedaily.com/releases/2012/02/120203091813.htm>.
Veterinärmedizinische Universität Wien. (2012, February 3). Parasites or not? Transposable elements in DNA of fruit flies may be beneficial. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2012/02/120203091813.htm
Veterinärmedizinische Universität Wien. "Parasites or not? Transposable elements in DNA of fruit flies may be beneficial." ScienceDaily. www.sciencedaily.com/releases/2012/02/120203091813.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) — The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) — For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) — An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins