Giant Viruses Are Ancient Living Organisms, Study Suggests
2012 09 17

From: NBCNews

Are viruses — DNA wrapped in a protein coat — alive? The latest research says yes.

Researchers have debated whether viruses, which have genes but no cellular structure, should be considered forms of life. A new study suggests they should, showing that giant viruses have some of the most ancient protein structures found in all organisms on the planet.


Giant viruses should be included reconstructions of the tree of life, researchers report in a new study. The mimivirus, shown here (small black hexagons) infecting an amoeba, is as big as some bacterial cells and shares some ancient protein structures with most organisms.


The researchers conducted a census of all the protein folds occurring in more than 1,000 organisms in the three traditional branches on the tree of life — bacteria, microbes known as archaea and eukaryotes. Giant viruses, which are considered "giant" based on the size of their genomes, also were included in the study because they are large and complex, with genomes rivaling some bacteria, University of Illinois researcher Gustavo Caetano-Anollés said in a statement.

For instance, the ocean’s largest virus, a giant virus called CroV, has genes that let it repair its genome, make sugars and gain more control over the very machinery the virus hijacks in host cells to replicate itself. (Since viruses are essentially DNA wrapped in a protein coat, they need the goods of a host to replicate themselves.)

Caetano-Anollés said his team looked at protein folds instead of genetic sequences because these structural features are like molecular fossils that are more stable over time. They assumed the folds that appear more often and in more groups are the most ancient structures.

"Just like paleontologists, we look at the parts of the system and how they change over time," Caetano-Anollés said.

They found that many of the most ancient protein folds in living organisms were present in the giant viruses, which "offers more evidence that viruses are embedded in the fabric of life," Caetano-Anollés said. The tree his team created had four clear branches, each representing a distinct "supergroup" — bacteria, archaea, eukaryotes and giant viruses.

The researchers said the study, which was published in the journal BMC Evolutionary Biology, also bolsters claims that giant viruses were once much more complex than they are now. A dramatic decline in their genomes over time likely reduced them to their current parasitic lifestyle, Caetano-Anollés said.


Article from: msnbc.msn.com





Related Articles
Vaccines combine to produce deadly virus
Common Cold Virus Attacks Cancer, Study Finds


Latest News from our Front Page

Magaluf bar where British girl was filmed performing sex acts on 24 men is shut down after police investigation into video
2014 07 26
Is this what the youth in Britain and Europe is spending their their energy, money, efforts and innocence on? The young girl, pictured, was lured into performing multiple sex acts after organisers offered a free drink although she thought a holiday was on offer* Council officials launched an official investigation after the video went viral Playhouse bar in Magaluf and entertainment ...
Prejudice is a Form of Common Sense - Hard-Wired Into the Human Brain, Says ASU Study
2014 07 26
Contrary to what most people believe, the tendency to be prejudiced is a form of common sense, hard-wired into the human brain through evolution as an adaptive response to protect our prehistoric ancestors from danger. So suggests a new study published by Arizona State University researchers in the May issue of the "Journal of Personality and Social Psychology," which contends that, ...
The State is a Bully
2014 07 24
In the history of Western philosophy and social theory, no really silly idea has been more successful than the theory of the social contract. It is in fact not a theory of the social contract. It is a theory of the political contract. It is the idea, promoted by Thomas Hobbes, John Locke, and Jean-Jacques Rousseau, that, at some point in ...
NATO Exercise in Ukraine Coincided with MH-17 Shoot-down
2014 07 24
Rapid Trident was omitted from the flurry of coverage on the shoot-down MH-17. From the U.S. Army in Europe website: Rapid Trident supports interoperability among Ukraine, the United States, NATO and Partnership for Peace member nations. The exercise helps prepare participants to operate successfully in a joint, multinational, integrated environment with host-nation support from civil and governmental agencies. ...
Warning of ’imminent’ terror attack in Norway
2014 07 24
Norwegians were warned Thursday of the concrete possibility of a terror attack occurring in that country at the hands of people with connections to an extremist group in Syria. A press conference was called in Oslo, Norway on Thursday where an announcement was made of a "possible concrete threat" to national security in that country from terrorists related to an extremist ...
More News »