Post by auntym on Apr 23, 2012 12:47:36 GMT -6
www.dailygalaxy.com/my_weblog/2012/04/xna-not-dna-may-form-basis-for-life-on-alien-planets-weekend-feature.html
XNA (Not DNA) May Form Basis for Life on Alien Planets[/color]
April 23, 2012
Synthetic biologists have discovered that six other molecules can could store genetic information and pass it on. A host of alternative nucleic acids have been made in labs over the years, but no one has made them work like DNA. Until now, everyone thought we were limited to RNA and DNA. This is the first time artificial molecules have been made to pass genes on to their descendants. The finding is a proof of principle that life needn't be based on DNA and RNA.
The ability to copy information from one molecule to another is fundamental to all life. Organisms pass their genes to their descendants, often with small changes, and as a result life can evolve over the generations. Barring a few exceptions, all known organisms use DNA as the information carrier.
"This unique ability of DNA and RNA to encode information can be implemented in other backbones," says Philipp Holliger of the MRC Laboratory of Molecular Biology in Cambridge, UK.
Holliger's team focused on six XNAs (xeno-nucleic acids). DNA and RNA are made of a sugar, a phosphate and a base. The XNAs had different sugars, and in some of them the sugars are replaced with completely different molecules. Synthetic XNA, with its different sugar backbone to natural DNA, can mimic many of the properties of the real thing.
Holliger and his team engineered enzymes that helped the six types of XNA to assemble and replicate genetic messages. The enzymes transcribed DNA into the various XNAs, then back into new DNA strands — with 95% accuracy or more.
A major challenge for the team was to create enzymes that could copy a gene from a DNA molecule to an XNA molecule, and other enzymes that could copy it back into DNA. Once they had created these enzymes, they were able to store information in each of the XNAs, copy it to DNA, and copy it back into a new XNA.
In effect, the first XNA passed its information on to the new one – albeit in a roundabout way. "The cycle we have is a bit like a retrovirus, which cycles between RNA and DNA," Holliger says. Because the XNAs can do this, they are capable of evolution.
CONTINUE READING: www.dailygalaxy.com/my_weblog/2012/04/xna-not-dna-may-form-basis-for-life-on-alien-planets-weekend-feature.h
XNA (Not DNA) May Form Basis for Life on Alien Planets[/color]
April 23, 2012
Synthetic biologists have discovered that six other molecules can could store genetic information and pass it on. A host of alternative nucleic acids have been made in labs over the years, but no one has made them work like DNA. Until now, everyone thought we were limited to RNA and DNA. This is the first time artificial molecules have been made to pass genes on to their descendants. The finding is a proof of principle that life needn't be based on DNA and RNA.
The ability to copy information from one molecule to another is fundamental to all life. Organisms pass their genes to their descendants, often with small changes, and as a result life can evolve over the generations. Barring a few exceptions, all known organisms use DNA as the information carrier.
"This unique ability of DNA and RNA to encode information can be implemented in other backbones," says Philipp Holliger of the MRC Laboratory of Molecular Biology in Cambridge, UK.
Holliger's team focused on six XNAs (xeno-nucleic acids). DNA and RNA are made of a sugar, a phosphate and a base. The XNAs had different sugars, and in some of them the sugars are replaced with completely different molecules. Synthetic XNA, with its different sugar backbone to natural DNA, can mimic many of the properties of the real thing.
Holliger and his team engineered enzymes that helped the six types of XNA to assemble and replicate genetic messages. The enzymes transcribed DNA into the various XNAs, then back into new DNA strands — with 95% accuracy or more.
A major challenge for the team was to create enzymes that could copy a gene from a DNA molecule to an XNA molecule, and other enzymes that could copy it back into DNA. Once they had created these enzymes, they were able to store information in each of the XNAs, copy it to DNA, and copy it back into a new XNA.
In effect, the first XNA passed its information on to the new one – albeit in a roundabout way. "The cycle we have is a bit like a retrovirus, which cycles between RNA and DNA," Holliger says. Because the XNAs can do this, they are capable of evolution.
CONTINUE READING: www.dailygalaxy.com/my_weblog/2012/04/xna-not-dna-may-form-basis-for-life-on-alien-planets-weekend-feature.h