Featured Research

from universities, journals, and other organizations

New insights into an ancient mechanism of mammalian evolution

Date:
January 12, 2012
Source:
European Molecular Biology Laboratory
Summary:
A team of geneticists and computational biologists have reveal how an ancient mechanism is involved in gene control and continues to drive genome evolution.

Over 150 million years of evolution, CTCF binding events have been added to the genome through repeated waves of retrotransposon expansion. Panel A shows examples of these events (top) and a sample CTCF binding event (bottom) that dates from before mammals began to branch out. Panel B shows in more detail how the CTCF protein interacts with mouse binding motif.
Credit: Image courtesy of European Molecular Biology Laboratory

Researchers in the UK have found a simple and widespread way in which DNA is remodeled in six mammalian species, including humans. The study, published in the journal Cell, sheds light on an ancient mechanism of evolution that is still at work in our genome.

Related Articles


A team of geneticists and computational biologists in the UK have reveal how an ancient mechanism is involved in gene control and continues to drive genome evolution. The new study is published in the journal Cell.

To function properly, mammalian tissues require the protein CTCF, which has several key activities including the regulation of genes and interaction with proteins in the cell's nucleus to alter gene activity. CTCF acts by binding to DNA and plays a role in diseases such as HIV infection and cancer. However, very little is known about the origin of the DNA sequences that are bound by CTCF.

In this study, the researchers used samples from six mammals (human, macaque, mouse, rat, dog, and short-tailed opossum) to pinpoint where CTCF binds to each genome. They discovered around 5000 sites that are present in most cell types and tissues, and that have not changed over hundreds of millions of years of mammalian evolution. Because these CTCF binding sites are conserved throughout evolution, the researchers believe that many might play an important role in gene regulation.

The team found an even larger number of locations where CTCF binds DNA in only one lineage or a single species. These additional sites represent a signature of important evolutionary changes since our last common ancestor -- legacies, in some cases, of the evolutionary path to humans. These newer CTCF sites are embedded inside virus-like stretches of DNA called 'retro-transposons'. Retro-transposons use a copy-paste mechanism to spread copies of themselves throughout the genome.

"We developed a new, integrated model of CTCF evolution, which explains the origin of these 5000 highly conserved CTCF binding events in mammals," said Paul Flicek of the European Molecular Biology Laboratory-European Bioinformatics Institute (EMBL-EBI) and the Wellcome Trust Sanger Institute. "Taken together, our findings provide fascinating insight into an ancient mechanism of evolution that is still actively changing our genome."

"CTCF is a key regulator involved in chromatin and gene expression remodelling, both of which are perturbed in the development of cancer. The gene expression and chromatin changes in cancer have also recently been relied on to predict the outcome of specific cancer treatments, which is why it is so important to have a detailed understanding of how particular parts of the genome are resistant or plastic to changes," said Duncan Odom of Cancer Research UK and the Wellcome Trust Sanger Institute.

The retro-transposon's copy-and-paste behaviour has long been considered totally self-serving. However, the study showed that when a retro-transposon containing a CTCF-binding sequence spreads around a mammal's genome, it can deposit functional CTCF binding sites in novel locations, altering the activity of distant genes.

"We looked at six mammalian species representing primates, marsupials, rodents and carnivores, and discovered a simple mechanism that they all use to remodel their DNA," explained Petra Schwalie of EMBL-EBI. "We also found that our distant ancestors also experienced the same complicated relationship between CTCF and retro-transposons."

Using molecular palaeontology techniques, the researchers were able to identify fossil traces of older retro-transposon expansions in the DNA around the shared CTCF binding locations, and showed that this process has been active for hundreds of millions of years.


Story Source:

The above story is based on materials provided by European Molecular Biology Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. Schmidt D., Schwalie P., Wilson M.D., et al. Waves of repeat-driven CTCF binding expansions have shaped mammalian genomes. Cell, 2012 DOI: 10.1016/j.cell.2011.11.058

Cite This Page:

European Molecular Biology Laboratory. "New insights into an ancient mechanism of mammalian evolution." ScienceDaily. ScienceDaily, 12 January 2012. <www.sciencedaily.com/releases/2012/01/120112134321.htm>.
European Molecular Biology Laboratory. (2012, January 12). New insights into an ancient mechanism of mammalian evolution. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2012/01/120112134321.htm
European Molecular Biology Laboratory. "New insights into an ancient mechanism of mammalian evolution." ScienceDaily. www.sciencedaily.com/releases/2012/01/120112134321.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Fossils & Ruins News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Ruins Thought To Be Port Actually Buried Greek City

Ruins Thought To Be Port Actually Buried Greek City

Newsy (Nov. 24, 2014) Media is calling it an "underwater Pompeii." Researchers have found ruins off the coast of Delos. Video provided by Newsy
Powered by NewsLook.com
Amphipolis Tomb Architraves Reveal Faces

Amphipolis Tomb Architraves Reveal Faces

AFP (Nov. 22, 2014) Faces in an area of mosaics is the latest find by archaeologists at a recently discovered tomb dating back to fourth century BC and the time of Alexander the Great in Greece. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
US Returns Looted Artifacts to Thailand

US Returns Looted Artifacts to Thailand

AFP (Nov. 19, 2014) The United States has returns over 500 vases, bowls, axes, and other ancient artifacts mostly from the Ban Chiang archaeological site which were illegally looted from Thailand decades ago. Duration: 01:13 Video provided by AFP
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