Scientists moved a step closer to synthesizing new life forms in the laboratory after researchers showed that artificial genetic material called XNA can be replicated in the test tube much like real DNA.
Researchers at the Medical Research Council Laboratory of Molecular Biology in the U.K. demonstrated for the first time a way to extract information from the artificial genetic molecules and mass produce copies of them. The finding, published today in the journal Science, shows that DNA and its sister molecule RNA may not be the only chemical structures upon which a living unit can be based.
”œLife is based on this amazing ability of DNA and RNA to store and propagate information,” said Philipp Holliger, a Medical Research Council molecular biologist and senior author on the study. ”œWe have shown that the basic functions of DNA and RNA can be recapitulated” with new artificial molecules.
The scientists invented a lab method for making copies of synthetic DNA. They also developed a way to make XNA fragments that evolve with desired properties. In particular, they created XNA fragments that could bind with great specificity to a molecular target in the HIV virus. The discovery could create a new platform for devising targeted drugs to treat a variety of diseases, researchers said.
While XNAs aren’t new, chemists have always had to make them one at a time, limiting their utility, Joyce said. With the new work, ”œif I give you a few XNAs in the morning, I can come back in the afternoon and you can give me trillions of copies.”
The XNA work provides a new way of developing designer nucleic acid drugs that could resist breakdown, or have other desirable properties, such as the ability to slip from the bloodstream into diseased cells, said Holliger.
XNA-based drugs ”œmight have a future to rival antibodies,” he said. Antibody drugs, such as Roche Holding AG (ROG)’s Avastin for cancer and Abbott Laboratories’ (ABT) (ABT) Humira for autoimmune diseases, have become some of the biggest selling therapies in recent years.
The research ”œis a tour-de-force” that could have ”œdirect therapeutic impact,” said Andrew Ellington, the Fraser Professor of Biochemistry at the Center for Systems and Synthetic Biology at the University of Texas in Austin, in an e- mail.
DNA alternative created by scientists
Artificial genetic material ”“ XNAs ”“ expected to reveal how molecules first replicated and drive biotechnology research
The Guardian, By Ian Sample, April 19
Scientists have created artificial genetic material that can store information and evolve over generations in a similar way to DNA ”“ a feat expected to drive research in medicine and biotechnology, and shed light on how molecules first replicated and assembled into life billions of years ago.
Ultimately, the creation of alternatives to DNA could enable scientists to make novel forms of life in the laboratory.
Researchers at the MRC Laboratory of Molecular Biology, in Cambridge, developed chemical procedures to turn DNA and RNA, the molecular bases for all known life, into six alternative genetic polymers called XNAs.
The process swaps the deoxyribose and ribose (the “d” and “r” in DNA and RNA) for other molecules. It was found the XNAs could form a double helix with DNA and were more stable than natural genetic material.
In the journal Science the researchers describe how they caused one of the XNAs to stick to a protein, an ability that might mean the polymers could deployed as drugs working like antibodies.
Philipp Holliger, a senior author on the study, said the work proved that two hallmarks of life ”“ heredity and evolution ”“ were possible using alternatives to natural genetic material.
“There is nothing Goldilocks about DNA and RNA,” Holliger told Science. “There is no overwhelming functional imperative for genetic systems or biology to be based on these two nucleic acids.”
In his article on the Cambridge study Joyce alludes to the potential dangers of synthetic genetics. He writes: “As one contemplates all the alternative life forms that might be possible with XNAs and other more exotic genetic molecules, the words of Arthur C Clarke come to mind. In 2010: Odyssey Two, HAL the computer tells humanity, ‘all these worlds are yours’, but warns ”“ ‘except [Jupiter's moon] Europa, attempt no landings there’. Synthetic biologists are beginning to frolic on the worlds of alternative genetics but must not tread into areas that have the potential to harm our biology.”
Science: Synthetic Genetic Polymers Capable of Heredity and Evolution
Genetic information storage and processing rely on just two polymers, DNA and RNA, yet whether their role reflects evolutionary history or fundamental functional constraints is currently unknown. With the use of polymerase evolution and design, we show that genetic information can be stored in and recovered from six alternative genetic polymers based on simple nucleic acid architectures not found in nature [xeno-nucleic acids (XNAs)]. We also select XNA aptamers, which bind their targets with high affinity and specificity, demonstrating that beyond heredity, specific XNAs have the capacity for Darwinian evolution and folding into defined structures. Thus, heredity and evolution, two hallmarks of life, are not limited to DNA and RNA but are likely to be emergent properties of polymers capable of information storage.