Scientists have turned the basic structure of DNA on its head: taking it from 4 bases to 12. This 12 base system has already been implemented in developing new forms of personalised medicine but now the researchers want to see if this more complex DNA can be self-sustaining.
Fifty-six years ago, Watson and Crick described DNA as containing base pairs made up of adenine, thymine, guanine and cytosine or A-T-G and C. As far as we know, all DNA on Earth uses only these four bases (before methylation) and RNA uses uracil in place of thymine. But now Steve Benner, and colleagues from Florida, have re-written these rules and his group are testing a system that uses eight more bases.
They hope the research will shed light on how life started on Earth, by producing a self-sustaining molecule capable of Darwinian evolution and reproduction. And it’s similar to the one that is thought to have appeared on Earth nearly four billion years ago.
At the American Chemical Society meeting this week, Benner described his ultimate goal to synthesize a similar molecule in his lab at the Foundation for Applied Molecular Evolution. His 12 letter genetic system is capable of nearly all of the actions that define a living thing — reproduction, growth and response to its environment.
"But it still isn't self-sustaining," Benner explained. "You need a graduate or post-doc to come in the morning and feed it. It doesn't look for its own food. No one has gotten that first step to work. If you start making estimates of how many molecules you have to look for in order to find one that does this, you're talking about 1 x 10^34 molecules." He said.
It sounds like something from the X-files but one day they may grow their very own alien DNA molecule in the lab.