A couple of scientists have found something big and potentially nasty lurking in the permafrosts of the Siberian tundra, something that could point to a threat to humans and something that raises some fundamental questions about 'life' itself, at least so far as creationists loons and, to be fair, many normal people think of it.
What Chantal Abergel and Jean-Michel Claverie of Aix-Marseille University, Marseille, France found was a previously unknown virus and the largest ever found, so large it is visible under a normal light microscope. It was taken from 30,000 year-old permafrost and proved to be perfectly viable.
The virus, a Pithovirus sibericum, so called because it resembles a Greek pithos or large earthenware jar, complete with a plug keeping its contents in, is 30% larger than the previous largest known virus, pandoravirus, also found by the same team, but has only a fifth of pandoravirus's 2500 genes. Those 500 genes are never-the-less enough for pithovirus to invade amoebae and turn them into machines for making for pithoviruses, and in a unique way, or at least in a way not seen before. The normal virus way of making more viruses is to invade a cell, or even just inject its DNA (or RNA) into the host cell, and then hijack the host genes and convert them into genes for making viruses.
Pithovirus, however, enters an amoeba and migrates to a vacuole (basically a chamber enclosed in a membrane inside the cell) and attach itself to the vacuole membrane, then removes the plug and empties its contents into the vacuole, where they then use their own DNA to make viruses, using the amoeba as a source of raw materials.
There are three competing theories of virus origins, which are not necessarily exclusive in that any could be correct for a given group of viruses.
- The Progressive Hypothesis, which sees the virus as a gene which has broken free and now exists as an independent entity, able to move between cells and integrate itself into the genome. It seems that a great deal of the human genome may have originated from these 'retroviruses' which have become a permanent fixture.
The Virus-First Hypothesis in which the virus is seen as having evolved directly from early replicators, and cells are seen as organised collections of virus-like particles, which viruses can use but have never become fully integrated into.
The Regressive Hypothesis where the virus is seen as an extreme form of parasitic reduction, rather like the bacteria which became incorporated into early cells to become organelles like mitochondria and chloroplasts.
As I mentioned above, not only does this present a problem for us, but the ease with which these viruses can be 'revived' (and I use the term loosely because there was no revival other than thawing needed) presents a problem for people who assume 'life' is some quality or substance which distinguishes 'living' things from inorganic substances; that somehow its presence marks the difference between a rock and a human or between a plank and a tree. We've all seen them come rushing excitedly onto the Internet fully primed by some creationist scam site or fundamentalist religious site, to ask their 'killer' question, "How did the first life arise from non-life?", only to tiptoe quietly away when asked how they are defining life, often after posting some gibberish about souls or breathing.
So, where was 'life' in these viruses for 30,000 years? Of course, it wasn't there since the viruses did not need to manage entropy and the anatomy and physiology was not doing any chemistry, so there was no life as most people would recognise it.
There is no reason to suppose that the first replicators were anything more than chemical reactions which occurred inevitably because the conditions were right, just as any other chemical reaction occurs. There was no initial 'life' because 'life' doesn't exist either as an entity or a characteristic in its own right and certainly not as some undefined magic ingredient. To ask where life came from is as daft as asking who set fire to the sun.
'via Blog this'