Astrobiologists are not certain whether alien would be a carbon-based like or not. Experiments are currently focusing on building alternative kinds of genetic codes and how these codes could evolve.One of the interesting topics discussed during a public event featuring biologist Richard Dawkins and physicist Lawrence Krauss was the thought that life could be built with an alien biochemistry. The event was attended by more than 3,000 people and was held at Arizona State University in Tempe.
Dawkins said that 99 percent of living things that used to exist are no longer in existence.
Krauss said that laws of physics and chemistry might favor carbon-based life resembling human.
Dawkins said that it is possible that life could exist in more diverse forms, provided that it has a code-carrying system just like DNA, copying itself with high fidelity.
In the same university, biochemist John Chaput was creating what he called TNA, an alternative version of DNA. He published the first evidence that TNA can undergo Darwinian evolution in January. Chaput agrees to Dawkins the need for genetic material for life to exist in more diverse forms just like DNA and RNA.
Alternative code-carriers were also experimented by NASA. The space agency claimed that scientists tried to substitute arsenic phosphorus of bacteria in their DNA. However, they never presented enough evidence that alternative life really existed, according to chemist Steve Benner.
Biochemist Rosemary Redfield duplicated the same process but the bacteria failed to grow when fed arsenic and no phosphorus.
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