Alien Virus

Never-before-seen GIANT virus found that's so unusual it may have come from Mars. Their DNA polymerase does cluster with those of other giant DNA viruses, suggesting the controversial existence of a fourth domain of life. Step far enough back from the tree of life and it begins to look quite simple. At its heart are just three stout branches, representing the three domains of life: bacteria, archaea and eukaryotes. But that's too simple, according to a band of biologists who believe we may be on the verge of discovering the fourth domain of life.

The Pandoravirus is one micrometre big - ten times the size of other viruses
It is found underwater but is not considered a threat to humans
The virus has been spotted off the coast of Chile and in an Australian pond
Only six per cent of its genes resemble those seen before on Earth.
This has led French researchers to believe the virus may have come from an ancient time or even another planet, such as Mars. The giant virus is only found underwater and is not thought to pose a serious risk to humans.

"First seen as poisons, then as life-forms, then biological chemicals, viruses today are thought of as being in a gray area between living and nonliving," writes molecular biologist Luis Villarreal in this in-depth feature for Scientific American. "They cannot replicate on their own but can do so in truly living cells and can also affect the behavior of their hosts profoundly."

The ambiguity stems in large part from viruses' paradoxical nature. On one hand, they posses many features that we associate with life – DNA and RNA, for example, and the capacity to evolve. They're also freakishly adept at hijacking the cellular machinery of their hosts, which they exploit to reproduce, spread and infect, at times with lethal efficiency. It's an impressive, if frightening, feat – especially for something that lacks the ability to produce its own proteins; because as devious as they are, viruses were long seen as relatively simple. They're quite small, physically, scientists thought, and their genomes are tiny. They have no cell wall. They don't even undergo metabolic processes. It's reasons like these that have seen viruses denied so much as a humble sprig on the tree of life. Ten years ago, however, the accidental discovery of mimivirus caused many scientists to reconsider the qualifications for inclusion in that tree's hallowed branches. Pandoraviruses, with their hulking size and unprecedented genomic composition, are sure to do the same.

Scottish mathematicians believe that 'self replicating' robotic space probes sent by alien civilisations could already be in our solar system.
The University of Edinburgh study warns that the probes are probably so hi-tech they appear invisible to us as we don't have technology advanced enough to detect them. They said probes that 'self replicate' and build new versions of themselves from dust and gas while traveling through space, could be in our solar system already.

Pandoravirus is a genus of very large viruses, with genomes much larger than those of any other known type of virus. Like the other very large viruses Mimivirus and Megavirus, Pandoravirus infects amoebas, but its genome, containing 1.9-2.5 megabases of DNA, is on the order of twice as large as that of Megavirus, and it differs greatly from the other large viruses in appearance and in genome structure. Pandoraviruses have a size of approximately 1 micron and a bloblike shape resembling some types of bacteria. The genome of the larger variant, Pandoravirus salinus, was reported to contain 2556 putative protein-coding sequences, of which only 6% had recognizable relationships with genes from other known organisms. The dissimilarity of the remaining genes to any that are known led the researchers to speculate that this virus may represent a previous unknown branch of the tree of life. However, experts not involved in the study have called that suggestion premature.

French evolutionary biologists Jean-Michel Claverie and Chantal Abergel at Aix-Marseille University originally called this Pandoravirus “NFL, new life form.” So big, they could see the NFL as a large, dark spot in their microscope (1 micrometer). That's ten times the size of other Earth viruses and only 6 to 7 percent of its genes resemble viruses seen on Earth. And these NFL viruses have a lot of genes - from 1,900 to 2,500 compared to only 10 genes in an Earth influenza virus. These new Pandoraviruses were found in water sampled off the coast of central Chile and a pond near Melbourne, Australia. The name Pandora was picked because it was like opening up a box of unknowns, but unlike the mythological Pandora's Box that releases evil to the world, these huge viruses are not thought to pose any major threat to human health. But if their origin is another planet such as Mars, “they are definitely part of something that we do not understand very well and that has the same complexity as cells,” says Gustavo Caetano-Anolles, Professor of Bioinformatics, Univ. of Illinois, who studies giant viruses.