domenica 20 aprile 2008

Are we 10 years away from artificial life?

In late August 2007, an Associated Press article put forth the claim that scientists were no more than 10 years away from creating artificial life -- and possibly as few as three. Could such a thing be possible? Scientists have made tremendous strides in decoding human and animal genomes, synthesizing DNA and cloning. Creating artificial, functioning biological organisms seems to present a tremendous leap beyond any of these abilities.
But some of the companies and researchers involved in the quest for artificial life believe that the 10-year time frame is possible. Not only that -- they say that the development of wet artificial life (as it's often called) will radically affect our views of biological life and our place in the universe.
The claims about the impending invention of artificial life may be a tad bold. Among the skeptics is Francis Collins, head of the Human Genome Project, says the 10-year time frame is too ambitious. Even so, the prospect of artificial life holds a lot of appeal, and we'll take a look at it in this article.
Wet artificial life is not a modified or genetically engineered organism. It's life created entirely from basic parts. But as we saw in our article about weird life, scientists don't have a rigorous, standardized definition of what life is. Even so, biologists have some basic ideas about which qualities artificial life needs to possess in order to be considered alive.
First, artificial life needs to have DNA or genetic code. It also needs to be able to reproduce and to pass on its genetic code. The life form then needs somewhere to place its genetic code, a protective casing or membrane, similar to a cell wall, that keeps the DNA and other parts together. The cell wall should also allow for normal biological processes to be carried out. In other words, it should be permeable enough to allow for the absorption of nutrients and relatively impermeable against pathogens. Once its basic parts are together, the organism should be self-sustaining: It should eat and metabolize food. Finally, the life form needs the ability to repair itself and to adapt and evolve.
Developing some of these characteristics presents many challenges to researchers. But one Harvard scientist predicted (in that same AP article) that by early 2007, great advances would be made in creating cell membranes [source: Associated Press]. Keeping an artificial organism alive for more than a few minutes or a few hours is also a challenge, though scientists can focus on strengthening the organisms after some of the initial hurdles are overcome.
To create DNA, some scientists advocate placing nucleotides (the building blocks of DNA) inside the cell casing. The nucleotides could somehow be combined to form DNA. That in itself might pose a challenge, as enzymes may be required to assemble the nucleotides, which might violate the "basic parts" rule for creating artificial life.
On the next page, we'll take a look at more challenges that stand between scientists and artificial life. We'll also consider this question: Will artificial life forms get out of control?
Science fiction books and movies are filled with examples of out-of-control machines, viruses, artificial organisms and artificial intelligences. These fictions represent the worst possible outcome, some people say, in "playing God." Some scientists offer the reassurance that by the time artificial organisms are actually created, more mechanisms would be in place to control them.
It's also important to remember that the wide range of diverse and complex organisms on Earth represents the product of almost four billion years of evolution. Even if the 10-year time frame is correct, scientists in 2017 won't be working with artificially created toxic plants, predatory animals or unstoppable viruses. Early synthetic life forms will be rather simple organisms of a few cells or less. In fact, more danger likely lies in the abuse of genetic engineering techniques to modify existing viruses to make them highly contagious or virulent.
To those who say that scientists don't have the right to "play God," advocates often say that creating artificial life is a natural extension of humanity's desire for progress and discovery. Research into artificial life may yield insights into some of biology's fundamental processes, though again, science fiction depictions of artificial creations run amok has likely not helped the case for artificial life.
Since there is some dispute about what defines both life and artificial life, we may see several premature claims of success from biologists. What would qualify as a success? Does it have to be a functional, complex, self-replicating organism, or would a simple bit of artificially created, self-replicating genetic code suffice? How basic must the ingredients be that are combined to create the organism? Francis Collins says that scientists would be "cheating" by using enzymes, which are themselves derived from life forms [source: PBS].
In what may represent an important first step, some scientists have already produced artificial viruses, but they did so by synthetically reproducing DNA of known viruses. They then injected this DNA into cells that weren't synthetically formed.
Once an artificial organism is created, how (and for how long) will it live? Collins believes that artificial life should be able to survive in a basic environment, perhaps in a simple sugar solution, without humans providing complicated chemicals [source: PBS]. Others might say that, at least at first, making some sort of microbe or organism that can survive briefly qualifies as a success -- even if it requires a lot of outside control or monitoring.
At the very least, some of the initial claims regarding artificial life will face significant scrutiny. In the coming years, expect an ongoing debate about what defines life, both "real" and artificial.
For more information about artificial life and other related topics, please check out the links on the next page.
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