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

Left and their big fat multi-cultural lie
2014 08 30
Picture the scene; a taxi is pulled over by an officer from South Yorkshire Police who finds a half-naked 12-year-old in the back of the cab so drunk or drugged that she can hardly stand. When interviewed, the taxi driver is found to have pornographic pictures of the girl on his phone. The officer hands back the phone and – no ...
Left and their big fat multi-cultural lie
2014 08 30
Picture the scene; a taxi is pulled over by an officer from South Yorkshire Police who finds a half-naked 12-year-old in the back of the cab so drunk or drugged that she can hardly stand. When interviewed, the taxi driver is found to have pornographic pictures of the girl on his phone. The officer hands back the phone and – no ...
Rotherham - Child sacrifice to diversity god
2014 08 30
It is sad to see how the once great nation of England has fallen. Britain now rivals North Korea for totalitarian control. If you are White, the wrong word can send you to jail. If you are non-White you are free to rape and kill the native British with impunity. If Henry the VIII came back from the grave, he could ...
Hungary’s Orban Bashes Liberal Immigration Policy
2014 08 29
Hungary’s Prime Minister Viktor Orban on Monday lashed out against immigration, setting one of the main policy objectives of his next term in power after winning parliamentary elections in April. “The goal is to cease immigration whatsoever,” said Hungary’s prime minister. “I think the current liberal immigration policy, which is considered obvious and morally based, is hypocrite,” Mr. Orban said. At a ...
China’s “Duplitecture” Cities Mimic the World’s Greatest Architectural Hits
2014 08 29
The best knockoffs in the world are in China. There are plenty of fake designer handbags and Rolexes, but China’s knockoffs go way beyond fashion. There are knockoff Apple stores that look so much like the real thing that some employees believe they are working in real Apple stores. And then there are entire knockoff cities. There are Venices with ...
More News »