The Technograph

To truly understand artificial life, one must first define what constitutes life. A common definition applicable to every life form on Earth is that it must possess either DNA or RNA and must be able to reproduce.

Four molecules form the backbone of DNA: adenine (A), guanine (G), thymine (T) and cytosine (C). Due to their bonding structure, their molecules attach to one another to form base pairs—C with G and A with T. Uracil (U), rather than thymine, is found in RNA. Each base pair is then combined with a few simple molecules to form nucleotides. Nucleotides are linearly ordered to form instructions that dictate each step in the creation of an organism. All species of life on Earth have various combinations and amounts of nucleotides.

Poliovirus has one of the simplest genomes because it contains only several thousand base pairs. In 1981, researchers discovered the G/C and A/U sequence in poliovirus’ RNA by using a machine to store the combinations in a computer’s memory. Scientists realized that if they could reconstruct the unlocked nucleotide sequence, they would be able to effectively create a living poliovirus from scratch.

As complex as they sound, nucleotides are just combinations of everyday atoms, like carbon and oxygen. Scientists can inexpensively create nucleotides through chemical processes and easily distribute them to researchers. (Nucleotides can actually be purchased by mail order!)

The Pentagon funded a program in the 1990’s to synthetically create poliovirus. Dr. Eckard Wimmer and his team at State University of New York at Stony Brook reached that goal in 2002, making poliovirus from manmade nucleotides. The synthetic virus was injected into mice, paralyzing and then killing the infected rodents.

Some scientists believe that Dr. Wimmer did not succeed in creating artificial life because a virus cannot reproduce on its own (it needs a host cell) and therefore it is not technically a living organism. Dr. Craig Venter is leading a team that is trying to create an artificial bacterium. Bacteria have more complex genomes than polioviruses and can reproduce on their own. In a 2008 paper, Dr. Venter’s group stated that they had decoded a bacterium’s genome, leaving only the important step of assembling a synthetic organism. Dr. Venter hopes that artificial bacteria will be used in part to create antibiotics and improve the environment.

Advances in artificial life have sparked considerable controversy in the scientific community. Smallpox is an extremely deadly virus that has been eradicated worldwide and now only exists in two highly guarded compounds, one in Russia and the other in the United States. It is feared that smallpox will be synthetically created and released by bioterrorists. Smallpox’s genome is less than one third as complex as the genome Dr. Venter’s team decoded.

While the direction artificial life will take is unknown at this time, it seems likely that complex forms of artificial life will play an increasing role in the society of the future.

Tagged with: alife, god, wimmer, venter, pentagon, artificial life