Giant Viruses Are Ancient Living Organisms, Study Suggests
2012-09-17 0:00

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

An Occupied Country
2016-02-06 5:42
When people refer to occupation governments or occupied countries, the first thought is often of military occupation—the garrisoning of foreign troops in one’s cities and civil administration by their military executives. The other vision is the trope of a cabal of Haredim sitting in a darkly-lit boardroom with a map of the world on the wall, a dated reading of ...
Immortal Symbols 1941
2016-02-06 2:07
Youtube description: Dutch film "Eeuwig Leevende Tekens" by Hamer - "Volksche Werkgemeenschap" (Folkish Study Group) - ancestral heritage, solar wheel, sun cross, tree of life, etc. Subs by Otharus - http://fryskednis.blogspot.com Source: youtube.com
Ex-German media boss admits on live radio the national news agenda is govt controlled
2016-02-06 1:32
f you really want a lesson in how the Western popular press works, this is it. Without question, Germany is the leading power in Europe. ZDF is its state broadcaster and most popular channel. Together with sister network ARD; German's are obliged to pay €17.98 per month to fund it. This week, during a radio event in Berlin, the retired head of ZDF ...
British teenager is gang raped by 'Moroccan' men after being dragged into a car in Spain
2016-02-06 1:09
A British teenager claims to have been gang-raped in a Spanish resort after being dragged into a car by a group of Moroccan men, it was reported today. The 18-year-old claimed she was attacked while walking home from work late at night in Sabinillas, near Marbella. Police are said to be investigating a group of Moroccan men in the area. A British teenager ...
8 Ways Racially Diverse Schools Hurt White Kids
2016-02-06 1:02
Description from YouTube: I argue against Mother Jones Propaganda Link to the original Mother Jones Article: 3 Ways White Kids Benefit Most From Racially Diverse Schools Links to all the articles and other citations mentioned in my video can be found here: docdro.id/6CpKvgA Source: youtube.com
More News »