And so the meaning of life continues-
How's this for bringing back the dead Kharn?
according to the Economist- it's synthetic.
Makes you wonder if people should be making life as they go along? Ethical? Bah!
Or perhaps God just mixed us up in his interstellar testtube-
Ok, so the article for you science types-
Artificial life
In the beginning
Nov 14th 2003
From Economist.com
The first fully functional synthetic virus has just been made
IT’S happened. Not in the flashing of an electrical storm over a ruined mediaeval castle, but in a laboratory a few kilometres outside Washington, DC. Someone has synthesised artificial life.
Well, more or less. The caveats are three. First, what they made was a naked genome, rather than a complete organism. Second, it was the genome of a virus, which some people might not regard as a proper living thing. Third, viral genomes have been made in the laboratory before.
To the first objection, the answer is that naked genome or not, the artificial Phi-X174 virus created by Craig Venter, Hamilton Smith and their colleagues at the Institute for Biological Energy Alternatives (IBEA), in Rockville, Maryland, was just as infectious as its natural counterpart, and reproduced just as effectively. To the second, it is true that viruses do not have their own energy-processing capabilities, which some regard as an essential characteristic of life. But viruses are parasites, and one of the features of a successful parasite is to get your host to do as many things as possible on your behalf, so that you can concentrate on your core competence—reproduction. Viruses have merely taken this feature to its logical conclusion.
To the third objection, the rebuttal is that although a group of biologists at the State University of New York, Stony Brook, did, indeed, once make something they said was the genome of a polio virus, it was so feeble that it could barely infect a cell and reproduce itself. It also took them years to put together, whereas the IBEA genome is fully functional and was the work of a fortnight. The Stony Brook effort, in other words, was a biological version of Sir Hiram Maxim’s heavier-than-air flying machine. It just about got off the ground. But history recognises the Wright brothers, not Maxim, as the true pioneers of powered flight.
Dr Venter and his colleagues, who will publish their result formally in the Proceedings of the National Academy of Sciences in a few weeks’ time, made their genome out of short stretches of DNA known as oligonucleotides. These were stitched together using a process called polymerase cycling assembly (PCA). This process is not new, but the team from IBEA refined and perfected it.
DNA molecules are, famously, double-stranded helices. Each helix is composed of molecular units called bases, and these pair up in a deterministic fashion across the strands. In effect, a DNA molecule is composed of pairs of these bases. The team from IBEA started with small pieces of DNA (they were 42 base pairs long). These pieces, known as oligonucleotides, can be made to order and purchased commercially. Each oligonucleotide corresponded to a stretch of the natural viral genome, but successive stretches overlapped with each other.
PCA works by mixing two oligonucleotides whose base-pair sequences overlap, separating the two strands of each molecule, and then allowing the strands to recombine. The overlap means than many strands will recombine with strands from the other oligonucleotide, leaving “bare ends” composed of single strands. These are then matched up with single bases, according to the deterministic pairing rule, to re-create a double-stranded molecule longer than either of the original oligonucleotides. Rinse and repeat, and you can build a piece of DNA several thousand base pairs long quite rapidly.
The Phi-X174 genome is short and compact. It is a mere 5,386 base pairs long, and it is able to pack all the genes necessary for the virus to take over a bacterial cell and use it to reproduce into that small space because they overlap each other. For Dr Venter and Dr Smith, however, Phi-X174 is merely proof of principle.
No once could accuse Craig Venter, the man who sequenced the first non-viral genome, and who led the private effort which sequenced the human genome, of being publicity shy. Picking Phi-X174 as the virus to copy had a nice historical resonance. This was the first genome ever to be sequenced, by Fred Sanger, of Cambridge University, in 1978. But Dr Venter’s real goal is to synthesise the genome of a bacterium. That, he reckons, could be done by stitching together about 60 pieces of DNA of the length his team has just created. And that, in turn, would mark the start of a new phase in biotechnology, a phase in which engineers shape entire organisms for human use rather than merely tinkering with the odd gene here and there.
In the meantime, though, the ability to make artificial viruses so quickly and easily raises some disturbing questions. Phi-X174 parasitises bacteria, and is no threat to human health. And most viruses are not infectious as “naked genomes” in the way that this one can be. Instead, they need a package of proteins to help them on their way. But the DNA sequences of several nasty viruses, including smallpox, are now known and publicly available. And as one of the team observed, the entry proteins for smallpox might be provided by a related but harmless virus. Let’s hope nobody tries.
