Living systems owe their existence to a pair of information-carrying molecules: DNA and RNA. These fundamental chemical forms possess two features essential for life: they display hereditymeaning they can encode and pass on genetic information, and they can adapt over time, through processes of Darwinian evolution.
A long-debated question is whether heredity and evolution could be performed by molecules other than DNA and RNA.
John Chaput, a researcher at ASU's Biodesign Institute, who recently published an article in Nature Chemistry describing the evolution of threose nucleic acids, joined a multidisciplinary team of scientists from England, Belgium and Denmark to extend these properties to other so-called Xenonucleic acids or XNA's.
The group demonstrates for the first time that six of these unnatural nucleic acid polymers are capable of sharing information with DNA. One of these XNAs, a molecule referred to as anhydrohexitol nucleic acid or HNA was capable of undergoing directed evolution and folding into biologically useful forms.
Their results appear in the current issue of Science.
The work sheds new light on questions concerning the origins of life and provides a range of practical applications for molecular medicine that were not previously available.
Nucleic acid aptamers, which have been engineered through in vitro selection to bind with various molecules, act in a manner similar to antibodieslatching onto their targets with high affinity and specificity. "This could be great for building new types of diagnostics and new types of biosensors," Chaput says, pointing out that XNAs are heartier molecules, not recognized by the natural enzymes that tend to degrade DNA and RNA. New therapeutics may also arise from experimental Xenobiology.
Both RNA and DNA embed data in their sequences of four nucleotidesinformation vital for conferring hereditary traits and for supplying the coded
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Arizona State University